commit f34d086fb7102fec895fd58b9e816b981b284c17 upstream.
module.c was renamed to main.c, but the Makefile directive was copy-pasted
verbatim with the old file name. Fix up the file name.
Fixes: cfc1d27789 ("module: Move all into module/")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/bc0cf790b4839c5e38e2fafc64271f620568a39e.1718092070.git.dvyukov@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2124d84db293ba164059077944e6b429ba530495 ]
The recursive aes-arm-bs module load situation reported by Russell King
is getting fixed in the crypto layer, but this in the meantime fixes the
"recursive load hangs forever" by just making the waiting for the first
module load be interruptible.
This should now match the old behavior before commit 9b9879fc03
("modules: catch concurrent module loads, treat them as idempotent"),
which used the different "wait for module to be ready" code in
module_patient_check_exists().
End result: a recursive module load will still block, but now a signal
will interrupt it and fail the second module load, at which point the
first module will successfully complete loading.
Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Cc: Russell King <linux@armlinux.org.uk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit cb5b81bc9a448f8db817566f60f92e2ea788ea0f ]
Russell King reported that the arm cbc(aes) crypto module hangs when
loaded, and Herbert Xu bisected it to commit 9b9879fc03 ("modules:
catch concurrent module loads, treat them as idempotent"), and noted:
"So what's happening here is that the first modprobe tries to load a
fallback CBC implementation, in doing so it triggers a load of the
exact same module due to module aliases.
IOW we're loading aes-arm-bs which provides cbc(aes). However, this
needs a fallback of cbc(aes) to operate, which is made out of the
generic cbc module + any implementation of aes, or ecb(aes). The
latter happens to also be provided by aes-arm-cb so that's why it
tries to load the same module again"
So loading the aes-arm-bs module ends up wanting to recursively load
itself, and the recursive load then ends up waiting for the original
module load to complete.
This is a regression, in that it used to be that we just tried to load
the module multiple times, and then as we went on to install it the
second time we would instead just error out because the module name
already existed.
That is actually also exactly what the original "catch concurrent loads"
patch did in commit 9828ed3f69 ("module: error out early on concurrent
load of the same module file"), but it turns out that it ends up being
racy, in that erroring out before the module has been fully initialized
will cause failures in dependent module loading.
See commit ac2263b588 (which was the revert of that "error out early")
commit for details about why erroring out before the module has been
initialized is actually fundamentally racy.
Now, for the actual recursive module load (as opposed to just
concurrently loading the same module twice), the race is not an issue.
At the same time it's hard for the kernel to see that this is recursion,
because the module load is always done from a usermode helper, so the
recursion is not some simple callchain within the kernel.
End result: this is not the real fix, but this at least adds a warning
for the situation (admittedly much too late for all the debugging pain
that Russell and Herbert went through) and if we can come to a
resolution on how to detect the recursion properly, this re-organizes
the code to make that easier.
Link: https://lore.kernel.org/all/ZrFHLqvFqhzykuYw@shell.armlinux.org.uk/
Reported-by: Russell King <linux@armlinux.org.uk>
Debugged-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stable-dep-of: 2124d84db293 ("module: make waiting for a concurrent module loader interruptible")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8f8cd6c0a43ed637e620bbe45a8d0e0c2f4d5130 ]
The synchronization here is to ensure the ordering of freeing of a module
init so that it happens before W+X checking. It is worth noting it is not
that the freeing was not happening, it is just that our sanity checkers
raced against the permission checkers which assume init memory is already
gone.
Commit 1a7b7d9220 ("modules: Use vmalloc special flag") moved calling
do_free_init() into a global workqueue instead of relying on it being
called through call_rcu(..., do_free_init), which used to allowed us call
do_free_init() asynchronously after the end of a subsequent grace period.
The move to a global workqueue broke the gaurantees for code which needed
to be sure the do_free_init() would complete with rcu_barrier(). To fix
this callers which used to rely on rcu_barrier() must now instead use
flush_work(&init_free_wq).
Without this fix, we still could encounter false positive reports in W+X
checking since the rcu_barrier() here can not ensure the ordering now.
Even worse, the rcu_barrier() can introduce significant delay. Eric
Chanudet reported that the rcu_barrier introduces ~0.1s delay on a
PREEMPT_RT kernel.
[ 0.291444] Freeing unused kernel memory: 5568K
[ 0.402442] Run /sbin/init as init process
With this fix, the above delay can be eliminated.
Link: https://lkml.kernel.org/r/20240227023546.2490667-1-changbin.du@huawei.com
Fixes: 1a7b7d9220 ("modules: Use vmalloc special flag")
Signed-off-by: Changbin Du <changbin.du@huawei.com>
Tested-by: Eric Chanudet <echanude@redhat.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Xiaoyi Su <suxiaoyi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 17fc8084aa8f9d5235f252fc3978db657dd77e92 ]
We consistently switched from kmalloc() to vmalloc() in module
decompression to prevent potential memory allocation failures with large
modules, however vmalloc() is not as memory-efficient and fast as
kmalloc().
Since we don't know in general the size of the workspace required by the
decompression algorithm, it is more reasonable to use kvmalloc()
consistently, also considering that we don't have special memory
requirements here.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3737df782c740b944912ed93420c57344b1cf864 ]
Use a similar approach as commit a419beac4a ("module/decompress: use
vmalloc() for zstd decompression workspace") and replace kmalloc() with
vmalloc() also for the gzip module decompression workspace.
In this case the workspace is represented by struct inflate_workspace
that can be fairly large for kmalloc() and it can potentially lead to
allocation errors on certain systems:
$ pahole inflate_workspace
struct inflate_workspace {
struct inflate_state inflate_state; /* 0 9544 */
/* --- cacheline 149 boundary (9536 bytes) was 8 bytes ago --- */
unsigned char working_window[32768]; /* 9544 32768 */
/* size: 42312, cachelines: 662, members: 2 */
/* last cacheline: 8 bytes */
};
Considering that there is no need to use continuous physical memory,
simply switch to vmalloc() to provide a more reliable in-kernel module
decompression.
Fixes: b1ae6dc41e ("module: add in-kernel support for decompressing")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.
arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.
Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.
Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
| module_emit_plt_entry+0x184/0x1cc
| apply_relocate_add+0x2bc/0x8e4
| load_module+0xe34/0x1bd4
| init_module_from_file+0x84/0xc0
| __arm64_sys_finit_module+0x1b8/0x27c
| invoke_syscall.constprop.0+0x5c/0x104
| do_el0_svc+0x58/0x160
| el0_svc+0x38/0x110
| el0t_64_sync_handler+0xc0/0xc4
| el0t_64_sync+0x190/0x194
Instead of duplicating module_init_layout_section()s logic, expose it.
Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
It has recently come to my attention that nvidia is circumventing the
protection added in 262e6ae708 ("modules: inherit
TAINT_PROPRIETARY_MODULE") by importing exports from their proprietary
modules into an allegedly GPL licensed module and then rexporting them.
Given that symbol_get was only ever intended for tightly cooperating
modules using very internal symbols it is logical to restrict it to
being used on EXPORT_SYMBOL_GPL and prevent nvidia from costly DMCA
Circumvention of Access Controls law suites.
All symbols except for four used through symbol_get were already exported
as EXPORT_SYMBOL_GPL, and the remaining four ones were switched over in
the preparation patches.
Fixes: 262e6ae708 ("modules: inherit TAINT_PROPRIETARY_MODULE")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Trying to restrict the '$'-prefix change to RISC-V caused some fallout,
so let's just treat all those symbols as special.
Fixes: c05780ef3c ("module: Ignore RISC-V mapping symbols too")
Link: https://lore.kernel.org/all/20230712015747.77263-1-wangkefeng.wang@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
RISC-V has an extended form of mapping symbols that we use to encode
the ISA when it changes in the middle of an ELF. This trips up modpost
as a build failure, I haven't yet verified it yet but I believe the
kallsyms difference should result in stacks looking sane again.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Vegard Nossum pointed out two different problems with the error handling
in init_module_from_file():
(a) the idempotent loading code didn't clean up properly in some error
cases, leaving the on-stack 'struct idempotent' element still in
the hash table
(b) failure to read the module file would nonsensically update the
'invalid_kread_bytes' stat counter with the error value
The first error is quite nasty, in that it can then cause subsequent
idempotent loads of that same file to access stale stack contents of the
previous failure. The case may not happen in any normal situation
(explaining all the "Tested-by's on the original change), and requires
admin privileges, but syzkaller triggers random bad behavior as a
result:
BUG: soft lockup in sys_finit_module
BUG: unable to handle kernel paging request in init_module_from_file
general protection fault in init_module_from_file
INFO: task hung in init_module_from_file
KASAN: out-of-bounds Read in init_module_from_file
KASAN: slab-out-of-bounds Read in init_module_from_file
...
The second error is fairly benign and just leads to nonsensical stats
(and has been around since the debug stats were added).
Vegard also provided a patch for the idempotent loading issue, but I'd
rather re-organize the code and make it more legible using another level
of helper functions than add the usual "goto out" error handling.
Link: https://lore.kernel.org/lkml/20230704100852.23452-1-vegard.nossum@oracle.com/
Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reported-by: syzbot+9c2bdc9d24e4a7abe741@syzkaller.appspotmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Remove the deprecated rule to build *.dtbo from *.dts
- Refactor section mismatch detection in modpost
- Fix bogus ARM section mismatch detections
- Fix error of 'make gtags' with O= option
- Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error with
the latest LLVM version
- Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
- Ignore more compiler-generated symbols for kallsyms
- Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
- Enable more kernel-doc warnings with W=2
- Refactor <linux/export.h> by generating KSYMTAB data by modpost
- Deprecate <asm/export.h> and <asm-generic/export.h>
- Remove the EXPORT_DATA_SYMBOL macro
- Move the check for static EXPORT_SYMBOL back to modpost, which makes
the build faster
- Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
- Warn missing MODULE_DESCRIPTION when building modules with W=1
- Make 'make clean' robust against too long argument error
- Exclude more objects from GCOV to fix CFI failures with GCOV
- Allow 'make modules_install' to install modules.builtin and
modules.builtin.modinfo even when CONFIG_MODULES is disabled
- Include modules.builtin and modules.builtin.modinfo in the linux-image
Debian package even when CONFIG_MODULES is disabled
- Revive "Entering directory" logging for the latest Make version
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Merge tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove the deprecated rule to build *.dtbo from *.dts
- Refactor section mismatch detection in modpost
- Fix bogus ARM section mismatch detections
- Fix error of 'make gtags' with O= option
- Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error
with the latest LLVM version
- Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
- Ignore more compiler-generated symbols for kallsyms
- Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
- Enable more kernel-doc warnings with W=2
- Refactor <linux/export.h> by generating KSYMTAB data by modpost
- Deprecate <asm/export.h> and <asm-generic/export.h>
- Remove the EXPORT_DATA_SYMBOL macro
- Move the check for static EXPORT_SYMBOL back to modpost, which makes
the build faster
- Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
- Warn missing MODULE_DESCRIPTION when building modules with W=1
- Make 'make clean' robust against too long argument error
- Exclude more objects from GCOV to fix CFI failures with GCOV
- Allow 'make modules_install' to install modules.builtin and
modules.builtin.modinfo even when CONFIG_MODULES is disabled
- Include modules.builtin and modules.builtin.modinfo in the
linux-image Debian package even when CONFIG_MODULES is disabled
- Revive "Entering directory" logging for the latest Make version
* tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits)
modpost: define more R_ARM_* for old distributions
kbuild: revive "Entering directory" for Make >= 4.4.1
kbuild: set correct abs_srctree and abs_objtree for package builds
scripts/mksysmap: Ignore prefixed KCFI symbols
kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb
kbuild: builddeb: always make modules_install, to install modules.builtin*
modpost: continue even with unknown relocation type
modpost: factor out Elf_Sym pointer calculation to section_rel()
modpost: factor out inst location calculation to section_rel()
kbuild: Disable GCOV for *.mod.o
kbuild: Fix CFI failures with GCOV
kbuild: make clean rule robust against too long argument error
script: modpost: emit a warning when the description is missing
kbuild: make modules_install copy modules.builtin(.modinfo)
linux/export.h: rename 'sec' argument to 'license'
modpost: show offset from symbol for section mismatch warnings
modpost: merge two similar section mismatch warnings
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
modpost: use null string instead of NULL pointer for default namespace
modpost: squash sym_update_namespace() into sym_add_exported()
...
The changes queued up for v6.5-rc1 for modules are pretty tame, mostly
code removal of moving of code. Only two minor functional changes are
made, the only one which stands out is Sebastian Andrzej Siewior's
simplification of module reference counting by removing preempt_disable()
and that has been tested on linux-next for well over a month without
no regressions. I'm now, I guess, also a kitchen sink for some kallsyms
changes.
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Merge tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull module updates from Luis Chamberlain:
"The changes queued up for modules are pretty tame, mostly code removal
of moving of code.
Only two minor functional changes are made, the only one which stands
out is Sebastian Andrzej Siewior's simplification of module reference
counting by removing preempt_disable() and that has been tested on
linux-next for well over a month without no regressions.
I'm now, I guess, also a kitchen sink for some kallsyms changes"
[ There was a mis-communication about the concurrent module load changes
that I had expected to come through Luis despite me authoring the
patch. So some of the module updates were left hanging in the email
ether, and I just committed them separately.
It's my bad - I should have made it more clear that I expected my
own patches to come through the module tree too. Now they missed
linux-next, but hopefully that won't cause any issues - Linus ]
* tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
kallsyms: make kallsyms_show_value() as generic function
kallsyms: move kallsyms_show_value() out of kallsyms.c
kallsyms: remove unsed API lookup_symbol_attrs
kallsyms: remove unused arch_get_kallsym() helper
module: Remove preempt_disable() from module reference counting.
This is the new-and-improved attempt at avoiding huge memory load spikes
when the user space boot sequence tries to load hundreds (or even
thousands) of redundant duplicate modules in parallel.
See commit 9828ed3f69 ("module: error out early on concurrent load of
the same module file") for background and an earlier failed attempt that
was reverted.
That earlier attempt just said "concurrently loading the same module is
silly, just open the module file exclusively and return -ETXTBSY if
somebody else is already loading it".
While it is true that concurrent module loads of the same module is
silly, the reason that earlier attempt then failed was that the
concurrently loaded module would often be a prerequisite for another
module.
Thus failing to load the prerequisite would then cause cascading
failures of the other modules, rather than just short-circuiting that
one unnecessary module load.
At the same time, we still really don't want to load the contents of the
same module file hundreds of times, only to then wait for an eventually
successful load, and have everybody else return -EEXIST.
As a result, this takes another approach, and treats concurrent module
loads from the same file as "idempotent" in the inode. So if one module
load is ongoing, we don't start a new one, but instead just wait for the
first one to complete and return the same return value as it did.
So unlike the first attempt, this does not return early: the intent is
not to speed up the boot, but to avoid a thundering herd problem in
allocating memory (both physical and virtual) for a module more than
once.
Also note that this does change behavior: it used to be that when you
had concurrent loads, you'd have one "winner" that would return success,
and everybody else would return -EEXIST.
In contrast, this idempotent logic goes all Oprah on the problem, and
says "You are a winner! And you are a winner! We are ALL winners". But
since there's no possible actual real semantic difference between "you
loaded the module" and "somebody else already loaded the module", this
is more of a feel-good change than an actual honest-to-goodness semantic
change.
Of course, any true Johnny-come-latelies that don't get caught in the
concurrency filter will still return -EEXIST. It's no different from
not even getting a seat at an Oprah taping. That's life.
See the long thread on the kernel mailing list about this all, which
includes some numbers for memory use before and after the patch.
Link: https://lore.kernel.org/lkml/20230524213620.3509138-1-mcgrof@kernel.org/
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Tested-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Rudi Heitbaum <rudi@heitbaum..com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This will simplify the next step, where we can then key off the inode to
do one idempotent module load.
Let's do the obvious re-organization in one step, and then the new code
in another.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 7b4537199a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.
For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().
The EXPORT_SYMBOL() compilation is split into two stages.
When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.
For example,
EXPORT_SYMBOL(foo);
EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);
will be encoded into the following assembly code:
.section ".export_symbol","a"
__export_symbol_foo:
.asciz "" /* license */
.asciz "" /* name space */
.balign 8
.quad foo /* symbol reference */
.previous
.section ".export_symbol","a"
__export_symbol_bar:
.asciz "GPL" /* license */
.asciz "BAR_NAMESPACE" /* name space */
.balign 8
.quad bar /* symbol reference */
.previous
They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.
Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:
KSYMTAB_FUNC(foo, "", "");
KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");
KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.
With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.
[1] Deprecate EXPORT_DATA_SYMBOL()
In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.
Commit 22823ab419 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.
However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.
In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.
There are only two users of EXPORT_DATA_SYMBOL:
EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S)
EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S)
They are transformed as follows and output into .vmlinux.export.c
KSYMTAB_DATA(empty_zero_page, "_gpl", "");
KSYMTAB_DATA(ia64_ivt, "", "");
The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().
EXPORT_DATA_SYMBOL() is now deprecated.
[2] merge <linux/export.h> and <asm-generic/export.h>
There are two similar header implementations:
include/linux/export.h for .c files
include/asm-generic/export.h for .S files
Ideally, the functionality should be consistent between them, but they
tend to diverge.
Commit 8651ec01da ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.
This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.
<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.
They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.
[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)
When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.
We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
While implementing support for in-kernel decompression in kmod,
finit_module() was returning a very suspicious value:
finit_module(3, "", MODULE_INIT_COMPRESSED_FILE) = 18446744072717407296
It turns out the check for module_get_next_page() failing is wrong,
and hence the decompression was not really taking place. Invert
the condition to fix it.
Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Cc: stable@kernel.org
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The preempt_disable() section in module_put() was added in commit
e1783a240f ("module: Use this_cpu_xx to dynamically allocate counters")
while the per-CPU counter were switched to another API. The API requires
that during the RMW operation the CPU remained the same.
This counting API was later replaced with atomic_t in commit
2f35c41f58 ("module: Replace module_ref with atomic_t refcnt")
Since this atomic_t replacement there is no need to keep preemption
disabled while the reference counter is modified.
Remove preempt_disable() from module_put(), __module_get() and
try_module_get().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Smatch warns:
kernel/module/stats.c:394 read_file_mod_stats()
warn: passing freed memory 'buf'
We are passing 'buf' to simple_read_from_buffer() after freeing it.
Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'.
Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Two newly introduced functions are declared in a header that is not
included before the definition, causing a warning with sparse or
'make W=1':
kernel/module/dups.c:118:6: error: no previous prototype for 'kmod_dup_request_exists_wait' [-Werror=missing-prototypes]
118 | bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/module/dups.c:220:6: error: no previous prototype for 'kmod_dup_request_announce' [-Werror=missing-prototypes]
220 | void kmod_dup_request_announce(char *module_name, int ret)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
Add an explicit include to ensure the prototypes match.
Fixes: 8660484ed1 ("module: add debugging auto-load duplicate module support")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304141440.DYO4NAzp-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The summary of the changes for this pull requests is:
* Song Liu's new struct module_memory replacement
* Nick Alcock's MODULE_LICENSE() removal for non-modules
* My cleanups and enhancements to reduce the areas where we vmalloc
module memory for duplicates, and the respective debug code which
proves the remaining vmalloc pressure comes from userspace.
Most of the changes have been in linux-next for quite some time except
the minor fixes I made to check if a module was already loaded
prior to allocating the final module memory with vmalloc and the
respective debug code it introduces to help clarify the issue. Although
the functional change is small it is rather safe as it can only *help*
reduce vmalloc space for duplicates and is confirmed to fix a bootup
issue with over 400 CPUs with KASAN enabled. I don't expect stable
kernels to pick up that fix as the cleanups would have also had to have
been picked up. Folks on larger CPU systems with modules will want to
just upgrade if vmalloc space has been an issue on bootup.
Given the size of this request, here's some more elaborate details
on this pull request.
The functional change change in this pull request is the very first
patch from Song Liu which replaces the struct module_layout with a new
struct module memory. The old data structure tried to put together all
types of supported module memory types in one data structure, the new
one abstracts the differences in memory types in a module to allow each
one to provide their own set of details. This paves the way in the
future so we can deal with them in a cleaner way. If you look at changes
they also provide a nice cleanup of how we handle these different memory
areas in a module. This change has been in linux-next since before the
merge window opened for v6.3 so to provide more than a full kernel cycle
of testing. It's a good thing as quite a bit of fixes have been found
for it.
Jason Baron then made dynamic debug a first class citizen module user by
using module notifier callbacks to allocate / remove module specific
dynamic debug information.
Nick Alcock has done quite a bit of work cross-tree to remove module
license tags from things which cannot possibly be module at my request
so to:
a) help him with his longer term tooling goals which require a
deterministic evaluation if a piece a symbol code could ever be
part of a module or not. But quite recently it is has been made
clear that tooling is not the only one that would benefit.
Disambiguating symbols also helps efforts such as live patching,
kprobes and BPF, but for other reasons and R&D on this area
is active with no clear solution in sight.
b) help us inch closer to the now generally accepted long term goal
of automating all the MODULE_LICENSE() tags from SPDX license tags
In so far as a) is concerned, although module license tags are a no-op
for non-modules, tools which would want create a mapping of possible
modules can only rely on the module license tag after the commit
8b41fc4454 ("kbuild: create modules.builtin without Makefile.modbuiltin
or tristate.conf"). Nick has been working on this *for years* and
AFAICT I was the only one to suggest two alternatives to this approach
for tooling. The complexity in one of my suggested approaches lies in
that we'd need a possible-obj-m and a could-be-module which would check
if the object being built is part of any kconfig build which could ever
lead to it being part of a module, and if so define a new define
-DPOSSIBLE_MODULE [0]. A more obvious yet theoretical approach I've
suggested would be to have a tristate in kconfig imply the same new
-DPOSSIBLE_MODULE as well but that means getting kconfig symbol names
mapping to modules always, and I don't think that's the case today. I am
not aware of Nick or anyone exploring either of these options. Quite
recently Josh Poimboeuf has pointed out that live patching, kprobes and
BPF would benefit from resolving some part of the disambiguation as
well but for other reasons. The function granularity KASLR (fgkaslr)
patches were mentioned but Joe Lawrence has clarified this effort has
been dropped with no clear solution in sight [1].
In the meantime removing module license tags from code which could never
be modules is welcomed for both objectives mentioned above. Some
developers have also welcomed these changes as it has helped clarify
when a module was never possible and they forgot to clean this up,
and so you'll see quite a bit of Nick's patches in other pull
requests for this merge window. I just picked up the stragglers after
rc3. LWN has good coverage on the motivation behind this work [2] and
the typical cross-tree issues he ran into along the way. The only
concrete blocker issue he ran into was that we should not remove the
MODULE_LICENSE() tags from files which have no SPDX tags yet, even if
they can never be modules. Nick ended up giving up on his efforts due
to having to do this vetting and backlash he ran into from folks who
really did *not understand* the core of the issue nor were providing
any alternative / guidance. I've gone through his changes and dropped
the patches which dropped the module license tags where an SPDX
license tag was missing, it only consisted of 11 drivers. To see
if a pull request deals with a file which lacks SPDX tags you
can just use:
./scripts/spdxcheck.py -f \
$(git diff --name-only commid-id | xargs echo)
You'll see a core module file in this pull request for the above,
but that's not related to his changes. WE just need to add the SPDX
license tag for the kernel/module/kmod.c file in the future but
it demonstrates the effectiveness of the script.
Most of Nick's changes were spread out through different trees,
and I just picked up the slack after rc3 for the last kernel was out.
Those changes have been in linux-next for over two weeks.
The cleanups, debug code I added and final fix I added for modules
were motivated by David Hildenbrand's report of boot failing on
a systems with over 400 CPUs when KASAN was enabled due to running
out of virtual memory space. Although the functional change only
consists of 3 lines in the patch "module: avoid allocation if module is
already present and ready", proving that this was the best we can
do on the modules side took quite a bit of effort and new debug code.
The initial cleanups I did on the modules side of things has been
in linux-next since around rc3 of the last kernel, the actual final
fix for and debug code however have only been in linux-next for about a
week or so but I think it is worth getting that code in for this merge
window as it does help fix / prove / evaluate the issues reported
with larger number of CPUs. Userspace is not yet fixed as it is taking
a bit of time for folks to understand the crux of the issue and find a
proper resolution. Worst come to worst, I have a kludge-of-concept [3]
of how to make kernel_read*() calls for modules unique / converge them,
but I'm currently inclined to just see if userspace can fix this
instead.
[0] https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/
[1] https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com
[2] https://lwn.net/Articles/927569/
[3] https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org
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Merge tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull module updates from Luis Chamberlain:
"The summary of the changes for this pull requests is:
- Song Liu's new struct module_memory replacement
- Nick Alcock's MODULE_LICENSE() removal for non-modules
- My cleanups and enhancements to reduce the areas where we vmalloc
module memory for duplicates, and the respective debug code which
proves the remaining vmalloc pressure comes from userspace.
Most of the changes have been in linux-next for quite some time except
the minor fixes I made to check if a module was already loaded prior
to allocating the final module memory with vmalloc and the respective
debug code it introduces to help clarify the issue. Although the
functional change is small it is rather safe as it can only *help*
reduce vmalloc space for duplicates and is confirmed to fix a bootup
issue with over 400 CPUs with KASAN enabled. I don't expect stable
kernels to pick up that fix as the cleanups would have also had to
have been picked up. Folks on larger CPU systems with modules will
want to just upgrade if vmalloc space has been an issue on bootup.
Given the size of this request, here's some more elaborate details:
The functional change change in this pull request is the very first
patch from Song Liu which replaces the 'struct module_layout' with a
new 'struct module_memory'. The old data structure tried to put
together all types of supported module memory types in one data
structure, the new one abstracts the differences in memory types in a
module to allow each one to provide their own set of details. This
paves the way in the future so we can deal with them in a cleaner way.
If you look at changes they also provide a nice cleanup of how we
handle these different memory areas in a module. This change has been
in linux-next since before the merge window opened for v6.3 so to
provide more than a full kernel cycle of testing. It's a good thing as
quite a bit of fixes have been found for it.
Jason Baron then made dynamic debug a first class citizen module user
by using module notifier callbacks to allocate / remove module
specific dynamic debug information.
Nick Alcock has done quite a bit of work cross-tree to remove module
license tags from things which cannot possibly be module at my request
so to:
a) help him with his longer term tooling goals which require a
deterministic evaluation if a piece a symbol code could ever be
part of a module or not. But quite recently it is has been made
clear that tooling is not the only one that would benefit.
Disambiguating symbols also helps efforts such as live patching,
kprobes and BPF, but for other reasons and R&D on this area is
active with no clear solution in sight.
b) help us inch closer to the now generally accepted long term goal
of automating all the MODULE_LICENSE() tags from SPDX license tags
In so far as a) is concerned, although module license tags are a no-op
for non-modules, tools which would want create a mapping of possible
modules can only rely on the module license tag after the commit
8b41fc4454 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf").
Nick has been working on this *for years* and AFAICT I was the only
one to suggest two alternatives to this approach for tooling. The
complexity in one of my suggested approaches lies in that we'd need a
possible-obj-m and a could-be-module which would check if the object
being built is part of any kconfig build which could ever lead to it
being part of a module, and if so define a new define
-DPOSSIBLE_MODULE [0].
A more obvious yet theoretical approach I've suggested would be to
have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
well but that means getting kconfig symbol names mapping to modules
always, and I don't think that's the case today. I am not aware of
Nick or anyone exploring either of these options. Quite recently Josh
Poimboeuf has pointed out that live patching, kprobes and BPF would
benefit from resolving some part of the disambiguation as well but for
other reasons. The function granularity KASLR (fgkaslr) patches were
mentioned but Joe Lawrence has clarified this effort has been dropped
with no clear solution in sight [1].
In the meantime removing module license tags from code which could
never be modules is welcomed for both objectives mentioned above. Some
developers have also welcomed these changes as it has helped clarify
when a module was never possible and they forgot to clean this up, and
so you'll see quite a bit of Nick's patches in other pull requests for
this merge window. I just picked up the stragglers after rc3. LWN has
good coverage on the motivation behind this work [2] and the typical
cross-tree issues he ran into along the way. The only concrete blocker
issue he ran into was that we should not remove the MODULE_LICENSE()
tags from files which have no SPDX tags yet, even if they can never be
modules. Nick ended up giving up on his efforts due to having to do
this vetting and backlash he ran into from folks who really did *not
understand* the core of the issue nor were providing any alternative /
guidance. I've gone through his changes and dropped the patches which
dropped the module license tags where an SPDX license tag was missing,
it only consisted of 11 drivers. To see if a pull request deals with a
file which lacks SPDX tags you can just use:
./scripts/spdxcheck.py -f \
$(git diff --name-only commid-id | xargs echo)
You'll see a core module file in this pull request for the above, but
that's not related to his changes. WE just need to add the SPDX
license tag for the kernel/module/kmod.c file in the future but it
demonstrates the effectiveness of the script.
Most of Nick's changes were spread out through different trees, and I
just picked up the slack after rc3 for the last kernel was out. Those
changes have been in linux-next for over two weeks.
The cleanups, debug code I added and final fix I added for modules
were motivated by David Hildenbrand's report of boot failing on a
systems with over 400 CPUs when KASAN was enabled due to running out
of virtual memory space. Although the functional change only consists
of 3 lines in the patch "module: avoid allocation if module is already
present and ready", proving that this was the best we can do on the
modules side took quite a bit of effort and new debug code.
The initial cleanups I did on the modules side of things has been in
linux-next since around rc3 of the last kernel, the actual final fix
for and debug code however have only been in linux-next for about a
week or so but I think it is worth getting that code in for this merge
window as it does help fix / prove / evaluate the issues reported with
larger number of CPUs. Userspace is not yet fixed as it is taking a
bit of time for folks to understand the crux of the issue and find a
proper resolution. Worst come to worst, I have a kludge-of-concept [3]
of how to make kernel_read*() calls for modules unique / converge
them, but I'm currently inclined to just see if userspace can fix this
instead"
Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]
* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
module: add debugging auto-load duplicate module support
module: stats: fix invalid_mod_bytes typo
module: remove use of uninitialized variable len
module: fix building stats for 32-bit targets
module: stats: include uapi/linux/module.h
module: avoid allocation if module is already present and ready
module: add debug stats to help identify memory pressure
module: extract patient module check into helper
modules/kmod: replace implementation with a semaphore
Change DEFINE_SEMAPHORE() to take a number argument
module: fix kmemleak annotations for non init ELF sections
module: Ignore L0 and rename is_arm_mapping_symbol()
module: Move is_arm_mapping_symbol() to module_symbol.h
module: Sync code of is_arm_mapping_symbol()
scripts/gdb: use mem instead of core_layout to get the module address
interconnect: remove module-related code
interconnect: remove MODULE_LICENSE in non-modules
zswap: remove MODULE_LICENSE in non-modules
zpool: remove MODULE_LICENSE in non-modules
x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
...
Core
----
- Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
default value allows for better BIG TCP performances.
- Reduce compound page head access for zero-copy data transfers.
- RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when possible.
- Threaded NAPI improvements, adding defer skb free support and unneeded
softirq avoidance.
- Address dst_entry reference count scalability issues, via false
sharing avoidance and optimize refcount tracking.
- Add lockless accesses annotation to sk_err[_soft].
- Optimize again the skb struct layout.
- Extends the skb drop reasons to make it usable by multiple
subsystems.
- Better const qualifier awareness for socket casts.
BPF
---
- Add skb and XDP typed dynptrs which allow BPF programs for more
ergonomic and less brittle iteration through data and variable-sized
accesses.
- Add a new BPF netfilter program type and minimal support to hook
BPF programs to netfilter hooks such as prerouting or forward.
- Add more precise memory usage reporting for all BPF map types.
- Adds support for using {FOU,GUE} encap with an ipip device operating
in collect_md mode and add a set of BPF kfuncs for controlling encap
params.
- Allow BPF programs to detect at load time whether a particular kfunc
exists or not, and also add support for this in light skeleton.
- Bigger batch of BPF verifier improvements to prepare for upcoming BPF
open-coded iterators allowing for less restrictive looping capabilities.
- Rework RCU enforcement in the verifier, add kptr_rcu and enforce BPF
programs to NULL-check before passing such pointers into kfunc.
- Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and in
local storage maps.
- Enable RCU semantics for task BPF kptrs and allow referenced kptr
tasks to be stored in BPF maps.
- Add support for refcounted local kptrs to the verifier for allowing
shared ownership, useful for adding a node to both the BPF list and
rbtree.
- Add BPF verifier support for ST instructions in convert_ctx_access()
which will help new -mcpu=v4 clang flag to start emitting them.
- Add ARM32 USDT support to libbpf.
- Improve bpftool's visual program dump which produces the control
flow graph in a DOT format by adding C source inline annotations.
Protocols
---------
- IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
indicates the provenance of the IP address.
- IPv6: optimize route lookup, dropping unneeded R/W lock acquisition.
- Add the handshake upcall mechanism, allowing the user-space
to implement generic TLS handshake on kernel's behalf.
- Bridge: support per-{Port, VLAN} neighbor suppression, increasing
resilience to nodes failures.
- SCTP: add support for Fair Capacity and Weighted Fair Queueing
schedulers.
- MPTCP: delay first subflow allocation up to its first usage. This
will allow for later better LSM interaction.
- xfrm: Remove inner/outer modes from input/output path. These are
not needed anymore.
- WiFi:
- reduced neighbor report (RNR) handling for AP mode
- HW timestamping support
- support for randomized auth/deauth TA for PASN privacy
- per-link debugfs for multi-link
- TC offload support for mac80211 drivers
- mac80211 mesh fast-xmit and fast-rx support
- enable Wi-Fi 7 (EHT) mesh support
Netfilter
---------
- Add nf_tables 'brouting' support, to force a packet to be routed
instead of being bridged.
- Update bridge netfilter and ovs conntrack helpers to handle
IPv6 Jumbo packets properly, i.e. fetch the packet length
from hop-by-hop extension header. This is needed for BIT TCP
support.
- The iptables 32bit compat interface isn't compiled in by default
anymore.
- Move ip(6)tables builtin icmp matches to the udptcp one.
This has the advantage that icmp/icmpv6 match doesn't load the
iptables/ip6tables modules anymore when iptables-nft is used.
- Extended netlink error report for netdevice in flowtables and
netdev/chains. Allow for incrementally add/delete devices to netdev
basechain. Allow to create netdev chain without device.
Driver API
----------
- Remove redundant Device Control Error Reporting Enable, as PCI core
has already error reporting enabled at enumeration time.
- Move Multicast DB netlink handlers to core, allowing devices other
then bridge to use them.
- Allow the page_pool to directly recycle the pages from safely
localized NAPI.
- Implement lockless TX queue stop/wake combo macros, allowing for
further code de-duplication and sanitization.
- Add YNL support for user headers and struct attrs.
- Add partial YNL specification for devlink.
- Add partial YNL specification for ethtool.
- Add tc-mqprio and tc-taprio support for preemptible traffic classes.
- Add tx push buf len param to ethtool, specifies the maximum number
of bytes of a transmitted packet a driver can push directly to the
underlying device.
- Add basic LED support for switch/phy.
- Add NAPI documentation, stop relaying on external links.
- Convert dsa_master_ioctl() to netdev notifier. This is a preparatory
work to make the hardware timestamping layer selectable by user
space.
- Add transceiver support and improve the error messages for CAN-FD
controllers.
New hardware / drivers
----------------------
- Ethernet:
- AMD/Pensando core device support
- MediaTek MT7981 SoC
- MediaTek MT7988 SoC
- Broadcom BCM53134 embedded switch
- Texas Instruments CPSW9G ethernet switch
- Qualcomm EMAC3 DWMAC ethernet
- StarFive JH7110 SoC
- NXP CBTX ethernet PHY
- WiFi:
- Apple M1 Pro/Max devices
- RealTek rtl8710bu/rtl8188gu
- RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset
- Bluetooth:
- Realtek RTL8821CS, RTL8851B, RTL8852BS
- Mediatek MT7663, MT7922
- NXP w8997
- Actions Semi ATS2851
- QTI WCN6855
- Marvell 88W8997
- Can:
- STMicroelectronics bxcan stm32f429
Drivers
-------
- Ethernet NICs:
- Intel (1G, icg):
- add tracking and reporting of QBV config errors.
- add support for configuring max SDU for each Tx queue.
- Intel (100G, ice):
- refactor mailbox overflow detection to support Scalable IOV
- GNSS interface optimization
- Intel (i40e):
- support XDP multi-buffer
- nVidia/Mellanox:
- add the support for linux bridge multicast offload
- enable TC offload for egress and engress MACVLAN over bond
- add support for VxLAN GBP encap/decap flows offload
- extend packet offload to fully support libreswan
- support tunnel mode in mlx5 IPsec packet offload
- extend XDP multi-buffer support
- support MACsec VLAN offload
- add support for dynamic msix vectors allocation
- drop RX page_cache and fully use page_pool
- implement thermal zone to report NIC temperature
- Netronome/Corigine:
- add support for multi-zone conntrack offload
- Solarflare/Xilinx:
- support offloading TC VLAN push/pop actions to the MAE
- support TC decap rules
- support unicast PTP
- Other NICs:
- Broadcom (bnxt): enforce software based freq adjustments only
on shared PHC NIC
- RealTek (r8169): refactor to addess ASPM issues during NAPI poll.
- Micrel (lan8841): add support for PTP_PF_PEROUT
- Cadence (macb): enable PTP unicast
- Engleder (tsnep): add XDP socket zero-copy support
- virtio-net: implement exact header length guest feature
- veth: add page_pool support for page recycling
- vxlan: add MDB data path support
- gve: add XDP support for GQI-QPL format
- geneve: accept every ethertype
- macvlan: allow some packets to bypass broadcast queue
- mana: add support for jumbo frame
- Ethernet high-speed switches:
- Microchip (sparx5): Add support for TC flower templates.
- Ethernet embedded switches:
- Broadcom (b54):
- configure 6318 and 63268 RGMII ports
- Marvell (mv88e6xxx):
- faster C45 bus scan
- Microchip:
- lan966x:
- add support for IS1 VCAP
- better TX/RX from/to CPU performances
- ksz9477: add ETS Qdisc support
- ksz8: enhance static MAC table operations and error handling
- sama7g5: add PTP capability
- NXP (ocelot):
- add support for external ports
- add support for preemptible traffic classes
- Texas Instruments:
- add CPSWxG SGMII support for J7200 and J721E
- Intel WiFi (iwlwifi):
- preparation for Wi-Fi 7 EHT and multi-link support
- EHT (Wi-Fi 7) sniffer support
- hardware timestamping support for some devices/firwmares
- TX beacon protection on newer hardware
- Qualcomm 802.11ax WiFi (ath11k):
- MU-MIMO parameters support
- ack signal support for management packets
- RealTek WiFi (rtw88):
- SDIO bus support
- better support for some SDIO devices
(e.g. MAC address from efuse)
- RealTek WiFi (rtw89):
- HW scan support for 8852b
- better support for 6 GHz scanning
- support for various newer firmware APIs
- framework firmware backwards compatibility
- MediaTek WiFi (mt76):
- P2P support
- mesh A-MSDU support
- EHT (Wi-Fi 7) support
- coredump support
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"Core:
- Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
default value allows for better BIG TCP performances
- Reduce compound page head access for zero-copy data transfers
- RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when
possible
- Threaded NAPI improvements, adding defer skb free support and
unneeded softirq avoidance
- Address dst_entry reference count scalability issues, via false
sharing avoidance and optimize refcount tracking
- Add lockless accesses annotation to sk_err[_soft]
- Optimize again the skb struct layout
- Extends the skb drop reasons to make it usable by multiple
subsystems
- Better const qualifier awareness for socket casts
BPF:
- Add skb and XDP typed dynptrs which allow BPF programs for more
ergonomic and less brittle iteration through data and
variable-sized accesses
- Add a new BPF netfilter program type and minimal support to hook
BPF programs to netfilter hooks such as prerouting or forward
- Add more precise memory usage reporting for all BPF map types
- Adds support for using {FOU,GUE} encap with an ipip device
operating in collect_md mode and add a set of BPF kfuncs for
controlling encap params
- Allow BPF programs to detect at load time whether a particular
kfunc exists or not, and also add support for this in light
skeleton
- Bigger batch of BPF verifier improvements to prepare for upcoming
BPF open-coded iterators allowing for less restrictive looping
capabilities
- Rework RCU enforcement in the verifier, add kptr_rcu and enforce
BPF programs to NULL-check before passing such pointers into kfunc
- Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and
in local storage maps
- Enable RCU semantics for task BPF kptrs and allow referenced kptr
tasks to be stored in BPF maps
- Add support for refcounted local kptrs to the verifier for allowing
shared ownership, useful for adding a node to both the BPF list and
rbtree
- Add BPF verifier support for ST instructions in
convert_ctx_access() which will help new -mcpu=v4 clang flag to
start emitting them
- Add ARM32 USDT support to libbpf
- Improve bpftool's visual program dump which produces the control
flow graph in a DOT format by adding C source inline annotations
Protocols:
- IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
indicates the provenance of the IP address
- IPv6: optimize route lookup, dropping unneeded R/W lock acquisition
- Add the handshake upcall mechanism, allowing the user-space to
implement generic TLS handshake on kernel's behalf
- Bridge: support per-{Port, VLAN} neighbor suppression, increasing
resilience to nodes failures
- SCTP: add support for Fair Capacity and Weighted Fair Queueing
schedulers
- MPTCP: delay first subflow allocation up to its first usage. This
will allow for later better LSM interaction
- xfrm: Remove inner/outer modes from input/output path. These are
not needed anymore
- WiFi:
- reduced neighbor report (RNR) handling for AP mode
- HW timestamping support
- support for randomized auth/deauth TA for PASN privacy
- per-link debugfs for multi-link
- TC offload support for mac80211 drivers
- mac80211 mesh fast-xmit and fast-rx support
- enable Wi-Fi 7 (EHT) mesh support
Netfilter:
- Add nf_tables 'brouting' support, to force a packet to be routed
instead of being bridged
- Update bridge netfilter and ovs conntrack helpers to handle IPv6
Jumbo packets properly, i.e. fetch the packet length from
hop-by-hop extension header. This is needed for BIT TCP support
- The iptables 32bit compat interface isn't compiled in by default
anymore
- Move ip(6)tables builtin icmp matches to the udptcp one. This has
the advantage that icmp/icmpv6 match doesn't load the
iptables/ip6tables modules anymore when iptables-nft is used
- Extended netlink error report for netdevice in flowtables and
netdev/chains. Allow for incrementally add/delete devices to netdev
basechain. Allow to create netdev chain without device
Driver API:
- Remove redundant Device Control Error Reporting Enable, as PCI core
has already error reporting enabled at enumeration time
- Move Multicast DB netlink handlers to core, allowing devices other
then bridge to use them
- Allow the page_pool to directly recycle the pages from safely
localized NAPI
- Implement lockless TX queue stop/wake combo macros, allowing for
further code de-duplication and sanitization
- Add YNL support for user headers and struct attrs
- Add partial YNL specification for devlink
- Add partial YNL specification for ethtool
- Add tc-mqprio and tc-taprio support for preemptible traffic classes
- Add tx push buf len param to ethtool, specifies the maximum number
of bytes of a transmitted packet a driver can push directly to the
underlying device
- Add basic LED support for switch/phy
- Add NAPI documentation, stop relaying on external links
- Convert dsa_master_ioctl() to netdev notifier. This is a
preparatory work to make the hardware timestamping layer selectable
by user space
- Add transceiver support and improve the error messages for CAN-FD
controllers
New hardware / drivers:
- Ethernet:
- AMD/Pensando core device support
- MediaTek MT7981 SoC
- MediaTek MT7988 SoC
- Broadcom BCM53134 embedded switch
- Texas Instruments CPSW9G ethernet switch
- Qualcomm EMAC3 DWMAC ethernet
- StarFive JH7110 SoC
- NXP CBTX ethernet PHY
- WiFi:
- Apple M1 Pro/Max devices
- RealTek rtl8710bu/rtl8188gu
- RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset
- Bluetooth:
- Realtek RTL8821CS, RTL8851B, RTL8852BS
- Mediatek MT7663, MT7922
- NXP w8997
- Actions Semi ATS2851
- QTI WCN6855
- Marvell 88W8997
- Can:
- STMicroelectronics bxcan stm32f429
Drivers:
- Ethernet NICs:
- Intel (1G, icg):
- add tracking and reporting of QBV config errors
- add support for configuring max SDU for each Tx queue
- Intel (100G, ice):
- refactor mailbox overflow detection to support Scalable IOV
- GNSS interface optimization
- Intel (i40e):
- support XDP multi-buffer
- nVidia/Mellanox:
- add the support for linux bridge multicast offload
- enable TC offload for egress and engress MACVLAN over bond
- add support for VxLAN GBP encap/decap flows offload
- extend packet offload to fully support libreswan
- support tunnel mode in mlx5 IPsec packet offload
- extend XDP multi-buffer support
- support MACsec VLAN offload
- add support for dynamic msix vectors allocation
- drop RX page_cache and fully use page_pool
- implement thermal zone to report NIC temperature
- Netronome/Corigine:
- add support for multi-zone conntrack offload
- Solarflare/Xilinx:
- support offloading TC VLAN push/pop actions to the MAE
- support TC decap rules
- support unicast PTP
- Other NICs:
- Broadcom (bnxt): enforce software based freq adjustments only on
shared PHC NIC
- RealTek (r8169): refactor to addess ASPM issues during NAPI poll
- Micrel (lan8841): add support for PTP_PF_PEROUT
- Cadence (macb): enable PTP unicast
- Engleder (tsnep): add XDP socket zero-copy support
- virtio-net: implement exact header length guest feature
- veth: add page_pool support for page recycling
- vxlan: add MDB data path support
- gve: add XDP support for GQI-QPL format
- geneve: accept every ethertype
- macvlan: allow some packets to bypass broadcast queue
- mana: add support for jumbo frame
- Ethernet high-speed switches:
- Microchip (sparx5): Add support for TC flower templates
- Ethernet embedded switches:
- Broadcom (b54):
- configure 6318 and 63268 RGMII ports
- Marvell (mv88e6xxx):
- faster C45 bus scan
- Microchip:
- lan966x:
- add support for IS1 VCAP
- better TX/RX from/to CPU performances
- ksz9477: add ETS Qdisc support
- ksz8: enhance static MAC table operations and error handling
- sama7g5: add PTP capability
- NXP (ocelot):
- add support for external ports
- add support for preemptible traffic classes
- Texas Instruments:
- add CPSWxG SGMII support for J7200 and J721E
- Intel WiFi (iwlwifi):
- preparation for Wi-Fi 7 EHT and multi-link support
- EHT (Wi-Fi 7) sniffer support
- hardware timestamping support for some devices/firwmares
- TX beacon protection on newer hardware
- Qualcomm 802.11ax WiFi (ath11k):
- MU-MIMO parameters support
- ack signal support for management packets
- RealTek WiFi (rtw88):
- SDIO bus support
- better support for some SDIO devices (e.g. MAC address from
efuse)
- RealTek WiFi (rtw89):
- HW scan support for 8852b
- better support for 6 GHz scanning
- support for various newer firmware APIs
- framework firmware backwards compatibility
- MediaTek WiFi (mt76):
- P2P support
- mesh A-MSDU support
- EHT (Wi-Fi 7) support
- coredump support"
* tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2078 commits)
net: phy: hide the PHYLIB_LEDS knob
net: phy: marvell-88x2222: remove unnecessary (void*) conversions
tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.
net: amd: Fix link leak when verifying config failed
net: phy: marvell: Fix inconsistent indenting in led_blink_set
lan966x: Don't use xdp_frame when action is XDP_TX
tsnep: Add XDP socket zero-copy TX support
tsnep: Add XDP socket zero-copy RX support
tsnep: Move skb receive action to separate function
tsnep: Add functions for queue enable/disable
tsnep: Rework TX/RX queue initialization
tsnep: Replace modulo operation with mask
net: phy: dp83867: Add led_brightness_set support
net: phy: Fix reading LED reg property
drivers: nfc: nfcsim: remove return value check of `dev_dir`
net: phy: dp83867: Remove unnecessary (void*) conversions
net: ethtool: coalesce: try to make user settings stick twice
net: mana: Check if netdev/napi_alloc_frag returns single page
net: mana: Rename mana_refill_rxoob and remove some empty lines
net: veth: add page_pool stats
...
The finit_module() system call can in the worst case use up to more than
twice of a module's size in virtual memory. Duplicate finit_module()
system calls are non fatal, however they unnecessarily strain virtual
memory during bootup and in the worst case can cause a system to fail
to boot. This is only known to currently be an issue on systems with
larger number of CPUs.
To help debug this situation we need to consider the different sources for
finit_module(). Requests from the kernel that rely on module auto-loading,
ie, the kernel's *request_module() API, are one source of calls. Although
modprobe checks to see if a module is already loaded prior to calling
finit_module() there is a small race possible allowing userspace to
trigger multiple modprobe calls racing against modprobe and this not
seeing the module yet loaded.
This adds debugging support to the kernel module auto-loader (*request_module()
calls) to easily detect duplicate module requests. To aid with possible bootup
failure issues incurred by this, it will converge duplicates requests to a
single request. This avoids any possible strain on virtual memory during
bootup which could be incurred by duplicate module autoloading requests.
Folks debugging virtual memory abuse on bootup can and should enable
this to see what pr_warn()s come on, to see if module auto-loading is to
blame for their wores. If they see duplicates they can further debug this
by enabling the module.enable_dups_trace kernel parameter or by enabling
CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS_TRACE.
Current evidence seems to point to only a few duplicates for module
auto-loading. And so the source for other duplicates creating heavy
virtual memory pressure due to larger number of CPUs should becoming
from another place (likely udev).
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This was caught by randconfig builds but does not show up in
build testing without CONFIG_MODULE_DECOMPRESS:
kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:229:42: error: 'invalid_mod_byte' undeclared (first use in this function); did you mean 'invalid_mod_bytes'?
229 | atomic_long_add(info->compressed_len, &invalid_mod_byte);
| ^~~~~~~~~~~~~~~~
| invalid_mod_bytes
Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
clang build reports
kernel/module/stats.c:307:34: error: variable
'len' is uninitialized when used here [-Werror,-Wuninitialized]
len = scnprintf(buf + 0, size - len,
^~~
At the start of this sequence, neither the '+ 0', nor the '- len' are needed.
So remove them and fix using 'len' uninitalized.
Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The new module statistics code mixes 64-bit types and wordsized 'long'
variables, which leads to build failures on 32-bit architectures:
kernel/module/stats.c: In function 'read_file_mod_stats':
kernel/module/stats.c:291:29: error: passing argument 1 of 'atomic64_read' from incompatible pointer type [-Werror=incompatible-pointer-types]
291 | total_size = atomic64_read(&total_mod_size);
x86_64-linux-ld: kernel/module/stats.o: in function `read_file_mod_stats':
stats.c:(.text+0x2b2): undefined reference to `__udivdi3'
To fix this, the code has to use one of the two types consistently.
Change them all to word-size types here.
Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
MODULE_INIT_COMPRESSED_FILE is defined in the uapi header, which
is not included indirectly from the normal linux/module.h, but
has to be pulled in explicitly:
kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:227:14: error: 'MODULE_INIT_COMPRESSED_FILE' undeclared (first use in this function)
227 | if (flags & MODULE_INIT_COMPRESSED_FILE)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The finit_module() system call can create unnecessary virtual memory
pressure for duplicate modules. This is because load_module() can in
the worse case allocate more than twice the size of a module in virtual
memory. This saves at least a full size of the module in wasted vmalloc
space memory by trying to avoid duplicates as soon as we can validate
the module name in the read module structure.
This can only be an issue if a system is getting hammered with userspace
loading modules. There are two ways to load modules typically on systems,
one is the kernel moduile auto-loading (*request_module*() calls in-kernel)
and the other is things like udev. The auto-loading is in-kernel, but that
pings back to userspace to just call modprobe. We already have a way to
restrict the amount of concurrent kernel auto-loads in a given time, however
that still allows multiple requests for the same module to go through
and force two threads in userspace racing to call modprobe for the same
exact module. Even though libkmod which both modprobe and udev does check
if a module is already loaded prior calling finit_module() races are
still possible and this is clearly evident today when you have multiple
CPUs.
To avoid memory pressure for such stupid cases put a stop gap for them.
The *earliest* we can detect duplicates from the modules side of things
is once we have blessed the module name, sadly after the first vmalloc
allocation. We can check for the module being present *before* a secondary
vmalloc() allocation.
There is a linear relationship between wasted virtual memory bytes and
the number of CPU counts. The reason is that udev ends up racing to call
tons of the same modules for each of the CPUs.
We can see the different linear relationships between wasted virtual
memory and CPU count during after boot in the following graph:
+----------------------------------------------------------------------------+
14GB |-+ + + + + *+ +-|
| **** |
| *** |
| ** |
12GB |-+ ** +-|
| ** |
| ** |
| ** |
| ** |
10GB |-+ ** +-|
| ** |
| ** |
| ** |
8GB |-+ ** +-|
waste | ** ### |
| ** #### |
| ** ####### |
6GB |-+ **** #### +-|
| * #### |
| * #### |
| ***** #### |
4GB |-+ ** #### +-|
| ** #### |
| ** #### |
| ** #### |
2GB |-+ ** ##### +-|
| * #### |
| * #### Before ******* |
| **## + + + + After ####### |
+----------------------------------------------------------------------------+
0 50 100 150 200 250 300
CPUs count
On the y-axis we can see gigabytes of wasted virtual memory during boot
due to duplicate module requests which just end up failing. Trying to
infer the slope this ends up being about ~463 MiB per CPU lost prior
to this patch. After this patch we only loose about ~230 MiB per CPU, for
a total savings of about ~233 MiB per CPU. This is all *just on bootup*!
On a 8vcpu 8 GiB RAM system using kdevops and testing against selftests
kmod.sh -t 0008 I see a saving in the *highest* side of memory
consumption of up to ~ 84 MiB with the Linux kernel selftests kmod
test 0008. With the new stress-ng module test I see a 145 MiB difference
in max memory consumption with 100 ops. The stress-ng module ops tests can be
pretty pathalogical -- it is not realistic, however it was used to
finally successfully reproduce issues which are only reported to happen on
system with over 400 CPUs [0] by just usign 100 ops on a 8vcpu 8 GiB RAM
system. Running out of virtual memory space is no surprise given the
above graph, since at least on x86_64 we're capped at 128 MiB, eventually
we'd hit a series of errors and once can use the above graph to
guestimate when. This of course will vary depending on the features
you have enabled. So for instance, enabling KASAN seems to make this
much worse.
The results with kmod and stress-ng can be observed and visualized below.
The time it takes to run the test is also not affected.
The kmod tests 0008:
The gnuplot is set to a range from 400000 KiB (390 Mib) - 580000 (566 Mib)
given the tests peak around that range.
cat kmod.plot
set term dumb
set output fileout
set yrange [400000:580000]
plot filein with linespoints title "Memory usage (KiB)"
Before:
root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-before.txt ^C
root@kmod ~ # sort -n -r log-0008-before.txt | head -1
528732
So ~516.33 MiB
After:
root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-after.txt ^C
root@kmod ~ # sort -n -r log-0008-after.txt | head -1
442516
So ~432.14 MiB
That's about 84 ~MiB in savings in the worst case. The graphs:
root@kmod ~ # gnuplot -e "filein='log-0008-before.txt'; fileout='graph-0008-before.txt'" kmod.plot
root@kmod ~ # gnuplot -e "filein='log-0008-after.txt'; fileout='graph-0008-after.txt'" kmod.plot
root@kmod ~ # cat graph-0008-before.txt
580000 +-----------------------------------------------------------------+
| + + + + + + + |
560000 |-+ Memory usage (KiB) ***A***-|
| |
540000 |-+ +-|
| |
| *A *AA*AA*A*AA *A*AA A*A*A *AA*A*AA*A A |
520000 |-+A*A*AA *AA*A *A*AA*A*AA *A*A A *A+-|
|*A |
500000 |-+ +-|
| |
480000 |-+ +-|
| |
460000 |-+ +-|
| |
| |
440000 |-+ +-|
| |
420000 |-+ +-|
| + + + + + + + |
400000 +-----------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
root@kmod ~ # cat graph-0008-after.txt
580000 +-----------------------------------------------------------------+
| + + + + + + + |
560000 |-+ Memory usage (KiB) ***A***-|
| |
540000 |-+ +-|
| |
| |
520000 |-+ +-|
| |
500000 |-+ +-|
| |
480000 |-+ +-|
| |
460000 |-+ +-|
| |
| *A *A*A |
440000 |-+A*A*AA*A A A*A*AA A*A*AA*A*AA*A*AA*A*AA*AA*A*AA*A*AA-|
|*A *A*AA*A |
420000 |-+ +-|
| + + + + + + + |
400000 +-----------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
The stress-ng module tests:
This is used to run the test to try to reproduce the vmap issues
reported by David:
echo 0 > /proc/sys/vm/oom_dump_tasks
./stress-ng --module 100 --module-name xfs
Prior to this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > baseline-stress-ng.txt
root@kmod ~ # sort -n -r baseline-stress-ng.txt | head -1
5046456
After this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > after-stress-ng.txt
root@kmod ~ # sort -n -r after-stress-ng.txt | head -1
4896972
5046456 - 4896972
149484
149484/1024
145.98046875000000000000
So this commit using stress-ng reveals saving about 145 MiB in memory
using 100 ops from stress-ng which reproduced the vmap issue reported.
cat kmod.plot
set term dumb
set output fileout
set yrange [4700000:5070000]
plot filein with linespoints title "Memory usage (KiB)"
root@kmod ~ # gnuplot -e "filein='baseline-stress-ng.txt'; fileout='graph-stress-ng-before.txt'" kmod-simple-stress-ng.plot
root@kmod ~ # gnuplot -e "filein='after-stress-ng.txt'; fileout='graph-stress-ng-after.txt'" kmod-simple-stress-ng.plot
root@kmod ~ # cat graph-stress-ng-before.txt
+---------------------------------------------------------------+
5.05e+06 |-+ + A + + + + + + +-|
| * Memory usage (KiB) ***A*** |
| * A |
5e+06 |-+ ** ** +-|
| ** * * A |
4.95e+06 |-+ * * A * A* +-|
| * * A A * * * * A |
| * * * * * * *A * * * A * |
4.9e+06 |-+ * * * A*A * A*AA*A A *A **A **A*A *+-|
| A A*A A * A * * A A * A * ** |
| * ** ** * * * * * * * |
4.85e+06 |-+ A A A ** * * ** *-|
| * * * * ** * |
| * A * * * * |
4.8e+06 |-+ * * * A A-|
| * * * |
4.75e+06 |-+ * * * +-|
| * ** |
| * + + + + + + ** + |
4.7e+06 +---------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
root@kmod ~ # cat graph-stress-ng-after.txt
+---------------------------------------------------------------+
5.05e+06 |-+ + + + + + + + +-|
| Memory usage (KiB) ***A*** |
| |
5e+06 |-+ +-|
| |
4.95e+06 |-+ +-|
| |
| |
4.9e+06 |-+ *AA +-|
| A*AA*A*A A A*AA*AA*A*AA*A A A A*A *AA*A*A A A*AA*AA |
| * * ** * * * ** * *** * |
4.85e+06 |-+* *** * * * * *** A * * +-|
| * A * * ** * * A * * |
| * * * * ** * * |
4.8e+06 |-+* * * A * * * +-|
| * * * A * * |
4.75e+06 |-* * * * * +-|
| * * * * * |
| * + * *+ + + + + * *+ |
4.7e+06 +---------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
[0] https://lkml.kernel.org/r/20221013180518.217405-1-david@redhat.com
Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Loading modules with finit_module() can end up using vmalloc(), vmap()
and vmalloc() again, for a total of up to 3 separate allocations in the
worst case for a single module. We always kernel_read*() the module,
that's a vmalloc(). Then vmap() is used for the module decompression,
and if so the last read buffer is freed as we use the now decompressed
module buffer to stuff data into our copy module. The last allocation is
specific to each architectures but pretty much that's generally a series
of vmalloc() calls or a variation of vmalloc to handle ELF sections with
special permissions.
Evaluation with new stress-ng module support [1] with just 100 ops
is proving that you can end up using GiBs of data easily even with all
care we have in the kernel and userspace today in trying to not load modules
which are already loaded. 100 ops seems to resemble the sort of pressure a
system with about 400 CPUs can create on module loading. Although issues
relating to duplicate module requests due to each CPU inucurring a new
module reuest is silly and some of these are being fixed, we currently lack
proper tooling to help diagnose easily what happened, when it happened
and who likely is to blame -- userspace or kernel module autoloading.
Provide an initial set of stats which use debugfs to let us easily scrape
post-boot information about failed loads. This sort of information can
be used on production worklaods to try to optimize *avoiding* redundant
memory pressure using finit_module().
There's a few examples that can be provided:
A 255 vCPU system without the next patch in this series applied:
Startup finished in 19.143s (kernel) + 7.078s (userspace) = 26.221s
graphical.target reached after 6.988s in userspace
And 13.58 GiB of virtual memory space lost due to failed module loading:
root@big ~ # cat /sys/kernel/debug/modules/stats
Mods ever loaded 67
Mods failed on kread 0
Mods failed on decompress 0
Mods failed on becoming 0
Mods failed on load 1411
Total module size 11464704
Total mod text size 4194304
Failed kread bytes 0
Failed decompress bytes 0
Failed becoming bytes 0
Failed kmod bytes 14588526272
Virtual mem wasted bytes 14588526272
Average mod size 171115
Average mod text size 62602
Average fail load bytes 10339140
Duplicate failed modules:
module-name How-many-times Reason
kvm_intel 249 Load
kvm 249 Load
irqbypass 8 Load
crct10dif_pclmul 128 Load
ghash_clmulni_intel 27 Load
sha512_ssse3 50 Load
sha512_generic 200 Load
aesni_intel 249 Load
crypto_simd 41 Load
cryptd 131 Load
evdev 2 Load
serio_raw 1 Load
virtio_pci 3 Load
nvme 3 Load
nvme_core 3 Load
virtio_pci_legacy_dev 3 Load
virtio_pci_modern_dev 3 Load
t10_pi 3 Load
virtio 3 Load
crc32_pclmul 6 Load
crc64_rocksoft 3 Load
crc32c_intel 40 Load
virtio_ring 3 Load
crc64 3 Load
The following screen shot, of a simple 8vcpu 8 GiB KVM guest with the
next patch in this series applied, shows 226.53 MiB are wasted in virtual
memory allocations which due to duplicate module requests during boot.
It also shows an average module memory size of 167.10 KiB and an an
average module .text + .init.text size of 61.13 KiB. The end shows all
modules which were detected as duplicate requests and whether or not
they failed early after just the first kernel_read*() call or late after
we've already allocated the private space for the module in
layout_and_allocate(). A system with module decompression would reveal
more wasted virtual memory space.
We should put effort now into identifying the source of these duplicate
module requests and trimming these down as much possible. Larger systems
will obviously show much more wasted virtual memory allocations.
root@kmod ~ # cat /sys/kernel/debug/modules/stats
Mods ever loaded 67
Mods failed on kread 0
Mods failed on decompress 0
Mods failed on becoming 83
Mods failed on load 16
Total module size 11464704
Total mod text size 4194304
Failed kread bytes 0
Failed decompress bytes 0
Failed becoming bytes 228959096
Failed kmod bytes 8578080
Virtual mem wasted bytes 237537176
Average mod size 171115
Average mod text size 62602
Avg fail becoming bytes 2758544
Average fail load bytes 536130
Duplicate failed modules:
module-name How-many-times Reason
kvm_intel 7 Becoming
kvm 7 Becoming
irqbypass 6 Becoming & Load
crct10dif_pclmul 7 Becoming & Load
ghash_clmulni_intel 7 Becoming & Load
sha512_ssse3 6 Becoming & Load
sha512_generic 7 Becoming & Load
aesni_intel 7 Becoming
crypto_simd 7 Becoming & Load
cryptd 3 Becoming & Load
evdev 1 Becoming
serio_raw 1 Becoming
nvme 3 Becoming
nvme_core 3 Becoming
t10_pi 3 Becoming
virtio_pci 3 Becoming
crc32_pclmul 6 Becoming & Load
crc64_rocksoft 3 Becoming
crc32c_intel 3 Becoming
virtio_pci_modern_dev 2 Becoming
virtio_pci_legacy_dev 1 Becoming
crc64 2 Becoming
virtio 2 Becoming
virtio_ring 2 Becoming
[0] https://github.com/ColinIanKing/stress-ng.git
[1] echo 0 > /proc/sys/vm/oom_dump_tasks
./stress-ng --module 100 --module-name xfs
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The patient module check inside add_unformed_module() is large
enough as we need it. It is a bit hard to read too, so just
move it to a helper and do the inverse checks first to help
shift the code and make it easier to read. The new helper then
is module_patient_check_exists().
To make this work we need to mvoe the finished_loading() up,
we do that without making any functional changes to that routine.
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Simplify the concurrency delimiter we use for kmod with the semaphore.
I had used the kmod strategy to try to implement a similar concurrency
delimiter for the kernel_read*() calls from the finit_module() path
so to reduce vmalloc() memory pressure. That effort didn't provide yet
conclusive results, but one thing that became clear is we can use
the suggested alternative solution with semaphores which Linus hinted
at instead of using the atomic / wait strategy.
I've stress tested this with kmod test 0008:
time /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
And I get only a *slight* delay. That delay however is small, a few
seconds for a full test loop run that runs 150 times, for about ~30-40
seconds. The small delay is worth the simplfication IMHO.
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Commit ac3b432839 ("module: replace module_layout with module_memory")
reworked the way to handle memory allocations to make it clearer. But it
lost in translation how we handled kmemleak_ignore() or kmemleak_not_leak()
for different ELF sections.
Fix this and clarify the comments a bit more. Contrary to the old way
of using kmemleak_ignore() for init.* ELF sections we stick now only to
kmemleak_not_leak() as per suggestion by Catalin Marinas so to avoid
any false positives and simplify the code.
Fixes: ac3b432839 ("module: replace module_layout with module_memory")
Reported-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The L0 symbol is generated when build module on LoongArch, ignore it in
modpost and when looking at module symbols, otherwise we can not see the
expected call trace.
Now is_arm_mapping_symbol() is not only for ARM, in order to reflect the
reality, rename is_arm_mapping_symbol() to is_mapping_symbol().
This is related with commit c17a253870 ("mksysmap: Fix the mismatch of
'L0' symbols in System.map").
(1) Simple test case
[loongson@linux hello]$ cat hello.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
static void test_func(void)
{
pr_info("This is a test\n");
dump_stack();
}
static int __init hello_init(void)
{
pr_warn("Hello, world\n");
test_func();
return 0;
}
static void __exit hello_exit(void)
{
pr_warn("Goodbye\n");
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
[loongson@linux hello]$ cat Makefile
obj-m:=hello.o
ccflags-y += -g -Og
all:
make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) clean
(2) Test environment
system: LoongArch CLFS 5.5
https://github.com/sunhaiyong1978/CLFS-for-LoongArch/releases/tag/5.0
It needs to update grub to avoid booting error "invalid magic number".
kernel: 6.3-rc1 with loongson3_defconfig + CONFIG_DYNAMIC_FTRACE=y
(3) Test result
Without this patch:
[root@linux hello]# insmod hello.ko
[root@linux hello]# dmesg
...
Hello, world
This is a test
...
Call Trace:
[<9000000000223728>] show_stack+0x68/0x18c
[<90000000013374cc>] dump_stack_lvl+0x60/0x88
[<ffff800002050028>] L0\x01+0x20/0x2c [hello]
[<ffff800002058028>] L0\x01+0x20/0x30 [hello]
[<900000000022097c>] do_one_initcall+0x88/0x288
[<90000000002df890>] do_init_module+0x54/0x200
[<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
[<90000000013382e8>] do_syscall+0x7c/0x94
[<9000000000221e3c>] handle_syscall+0xbc/0x158
With this patch:
[root@linux hello]# insmod hello.ko
[root@linux hello]# dmesg
...
Hello, world
This is a test
...
Call Trace:
[<9000000000223728>] show_stack+0x68/0x18c
[<90000000013374cc>] dump_stack_lvl+0x60/0x88
[<ffff800002050028>] test_func+0x28/0x34 [hello]
[<ffff800002058028>] hello_init+0x28/0x38 [hello]
[<900000000022097c>] do_one_initcall+0x88/0x288
[<90000000002df890>] do_init_module+0x54/0x200
[<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
[<90000000013382e8>] do_syscall+0x7c/0x94
[<9000000000221e3c>] handle_syscall+0xbc/0x158
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Tested-by: Youling Tang <tangyouling@loongson.cn> # for LoongArch
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
In order to avoid duplicated code, move is_arm_mapping_symbol() to
include/linux/module_symbol.h, then remove is_arm_mapping_symbol()
in the other places.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
After commit 2e3a10a155 ("ARM: avoid ARM binutils leaking ELF local
symbols") and commit d6b732666a ("modpost: fix undefined behavior of
is_arm_mapping_symbol()"), many differences of is_arm_mapping_symbol()
exist in kernel/module/kallsyms.c and scripts/mod/modpost.c, just sync
the code to keep consistent.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
already_uses() is unnecessarily chatty.
`modprobe i915` yields 491 messages like:
[ 64.108744] i915 uses drm!
This is a normal situation, and isn't worth all the log entries.
NOTE: I've preserved the "does not use %s" messages, which happens
less often, but does happen. Its not clear to me what it tells a
reader, or what info might improve the pr_debug's utility.
[ 6847.584999] main:already_uses:569: amdgpu does not use ttm!
[ 6847.585001] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585014] main:already_uses:569: amdgpu does not use drm!
[ 6847.585016] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585024] main:already_uses:569: amdgpu does not use drm_display_helper!
[ 6847.585025] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585084] main:already_uses:569: amdgpu does not use drm_kms_helper!
[ 6847.585086] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585175] main:already_uses:569: amdgpu does not use drm_buddy!
[ 6847.585176] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585202] main:already_uses:569: amdgpu does not use i2c_algo_bit!
[ 6847.585204] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585249] main:already_uses:569: amdgpu does not use gpu_sched!
[ 6847.585250] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585314] main:already_uses:569: amdgpu does not use video!
[ 6847.585315] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585409] main:already_uses:569: amdgpu does not use iommu_v2!
[ 6847.585410] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585816] main:already_uses:569: amdgpu does not use drm_ttm_helper!
[ 6847.585818] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6848.762268] dyndbg: add-module: amdgpu.2533 sites
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
move_module() pr_debug's "Final section addresses for $modname".
Add section addresses to the message, for anyone looking at these.
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The pr_debug("Absolute symbol" ..) reports value, (which is usually
0), but not the name, which is more informative. So add it.
no functional changes
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
layout_sections() and move_module() each issue ~50 messages for each
module loaded. Add mod-name into their 2 header lines, to help the
reader find his module.
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The kernel/kmod.c is already only built if we enabled modules, so
just stuff it under kernel/module/kmod.c and unify the MAINTAINERS
file for it.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The setup_load_info() was actually had ELF validation checks of its
own. To later cache useful variables as an secondary step just means
looping again over the ELF sections we just validated. We can simply
keep tabs of the key sections of interest as we validate the module
ELF section in one swoop, so do that and merge the two routines
together.
Expand a bit on the documentation / intent / goals.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The integrity of the struct module we load is important, and although
our ELF validator already checks that the module section must match
struct module, add a stop-gap check before we memcpy() the final minted
module. This also makes those inspecting the code what the goal is.
While at it, clarify the goal behind updating the sh_addr address.
The current comment is pretty misleading.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The ELF ".gnu.linkonce.this_module" section is special, it is what we
use to construct the struct module __this_module, which THIS_MODULE
points to. When userspace loads a module we always deal first with a
copy of the userspace buffer, and twiddle with the userspace copy's
version of the struct module. Eventually we allocate memory to do a
memcpy() of that struct module, under the assumption that the module
size is right. But we have no validity checks against the size or
the requirements for the section.
Add some validity checks for the special module section early and while
at it, cache the module section index early, so we don't have to do that
later.
While at it, just move over the assigment of the info->mod to make the
code clearer. The validity checker also adds an explicit size check to
ensure the module section size matches the kernel's run time size for
sizeof(struct module). This should prevent sloppy loads of modules
which are built today *without* actually increasing the size of
the struct module. A developer today can for example expand the size
of struct module, rebuild a directoroy 'make fs/xfs/' for example and
then try to insmode the driver there. That module would in effect have
an incorrect size. This new size check would put a stop gap against such
mistakes.
This also makes the entire goal of ".gnu.linkonce.this_module" pretty
clear. Before this patch verification of the goal / intent required some
Indian Jones whips, torches and cleaning up big old spider webs.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Converge on a compromise: so long as we have a module hit our linked
list of modules we taint. That is, the module was about to become live.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Dmitry Vyukov