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Merge tag 'livepatching-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching updates from Petr Mladek:
- Correctly handle kobjects when a livepatch init fails
- Avoid CPU hogging when searching for many livepatched symbols
- Add livepatch API page into documentation
* tag 'livepatching-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
livepatch: Avoid CPU hogging with cond_resched
livepatch: Fix missing unlock on error in klp_enable_patch()
livepatch: Fix kobject refcount bug on klp_init_patch_early failure path
Documentation: livepatch: Add livepatch API page
When enabling a klp patch with klp_enable_patch(), klp_init_patch_early()
is invoked to initialize the kobjects for the patch itself, as well as the
'struct klp_object' and 'struct klp_func' objects that comprise it.
However, there are some error paths in klp_enable_patch() where some
kobjects may have been initialized with kobject_init(), but an error code
is still returned due to e.g. a 'struct klp_object' having a NULL funcs
pointer.
In these paths, the initial reference of the kobject of the 'struct
klp_patch' may never be released, along with one or more of its objects and
their functions, as kobject_put() is not invoked on the cleanup path if
klp_init_patch_early() returns an error code.
For example, if an object entry such as the following were added to the
sample livepatch module's klp patch, it would cause the vmlinux klp_object,
and its klp_func which updates 'cmdline_proc_show', to never be released:
static struct klp_object objs[] = {
{
/* name being NULL means vmlinux */
.funcs = funcs,
},
{
/* NULL funcs -- would cause reference leak */
.name = "kvm",
}, { }
};
Without this change, if CONFIG_DEBUG_KOBJECT is enabled, and the sample klp
patch is loaded, the kobjects (the patch, the vmlinux 'struct klp_object',
and its func) are observed as initialized, but never released, in the dmesg
log output. With the change, these kobject references no longer fail to be
released as the error case is properly handled before they are initialized.
Signed-off-by: David Vernet <void@manifault.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The livepatch subsystem has several exported functions and objects with
kerneldoc comments. Though the livepatch documentation contains handwritten
descriptions of all of these exported functions, they are currently not
pulled into the docs build using the kernel-doc directive.
In order to allow readers of the documentation to see the full kerneldoc
comments in the generated documentation files, this change adds a new
Documentation/livepatch/api.rst page which contains kernel-doc directives
to link the kerneldoc comments directly in the documentation. With this,
all of the hand-written descriptions of the APIs now cross-reference the
kerneldoc comments on the new Livepatching APIs page, and running
./scripts/find-unused-docs.sh on kernel/livepatch no longer shows any files
as missing documentation.
Note that all of the handwritten API descriptions were left alone with the
exception of Documentation/livepatch/system-state.rst, which was updated to
allow the cross-referencing to work correctly. The file now follows the
cross-referencing formatting guidance specified in
Documentation/doc-guide/kernel-doc.rst. Furthermore, some comments around
klp_shadow_free_all() were updated to say <_, id> rather than <*, id> to
match the rest of the file, and to prevent the docs build from emitting an
"Inline emphasis start-string without end string" error.
Signed-off-by: David Vernet <void@manifault.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20211221145743.4098360-1-void@manifault.com
- kprobes: Restructured stack unwinder to show properly on x86 when a stack
dump happens from a kretprobe callback.
- Fix to bootconfig parsing
- Have tracefs allow owner and group permissions by default (only denying
others). There's been pressure to allow non root to tracefs in a
controlled fashion, and using groups is probably the safest.
- Bootconfig memory managament updates.
- Bootconfig clean up to have the tools directory be less dependent on
changes in the kernel tree.
- Allow perf to be traced by function tracer.
- Rewrite of function graph tracer to be a callback from the function tracer
instead of having its own trampoline (this change will happen on an arch
by arch basis, and currently only x86_64 implements it).
- Allow multiple direct trampolines (bpf hooks to functions) be batched
together in one synchronization.
- Allow histogram triggers to add variables that can perform calculations
against the event's fields.
- Use the linker to determine architecture callbacks from the ftrace
trampoline to allow for proper parameter prototypes and prevent warnings
from the compiler.
- Extend histogram triggers to key off of variables.
- Have trace recursion use bit magic to determine preempt context over if
branches.
- Have trace recursion disable preemption as all use cases do anyway.
- Added testing for verification of tracing utilities.
- Various small clean ups and fixes.
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Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- kprobes: Restructured stack unwinder to show properly on x86 when a
stack dump happens from a kretprobe callback.
- Fix to bootconfig parsing
- Have tracefs allow owner and group permissions by default (only
denying others). There's been pressure to allow non root to tracefs
in a controlled fashion, and using groups is probably the safest.
- Bootconfig memory managament updates.
- Bootconfig clean up to have the tools directory be less dependent on
changes in the kernel tree.
- Allow perf to be traced by function tracer.
- Rewrite of function graph tracer to be a callback from the function
tracer instead of having its own trampoline (this change will happen
on an arch by arch basis, and currently only x86_64 implements it).
- Allow multiple direct trampolines (bpf hooks to functions) be batched
together in one synchronization.
- Allow histogram triggers to add variables that can perform
calculations against the event's fields.
- Use the linker to determine architecture callbacks from the ftrace
trampoline to allow for proper parameter prototypes and prevent
warnings from the compiler.
- Extend histogram triggers to key off of variables.
- Have trace recursion use bit magic to determine preempt context over
if branches.
- Have trace recursion disable preemption as all use cases do anyway.
- Added testing for verification of tracing utilities.
- Various small clean ups and fixes.
* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
tracing/histogram: Fix semicolon.cocci warnings
tracing/histogram: Fix documentation inline emphasis warning
tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
tracing: Show size of requested perf buffer
bootconfig: Initialize ret in xbc_parse_tree()
ftrace: do CPU checking after preemption disabled
ftrace: disable preemption when recursion locked
tracing/histogram: Document expression arithmetic and constants
tracing/histogram: Optimize division by a power of 2
tracing/histogram: Covert expr to const if both operands are constants
tracing/histogram: Simplify handling of .sym-offset in expressions
tracing: Fix operator precedence for hist triggers expression
tracing: Add division and multiplication support for hist triggers
tracing: Add support for creating hist trigger variables from literal
selftests/ftrace: Stop tracing while reading the trace file by default
MAINTAINERS: Update KPROBES and TRACING entries
test_kprobes: Move it from kernel/ to lib/
docs, kprobes: Remove invalid URL and add new reference
samples/kretprobes: Fix return value if register_kretprobe() failed
lib/bootconfig: Fix the xbc_get_info kerneldoc
...
As the documentation explained, ftrace_test_recursion_trylock()
and ftrace_test_recursion_unlock() were supposed to disable and
enable preemption properly, however currently this work is done
outside of the function, which could be missing by mistake.
And since the internal using of trace_test_and_set_recursion()
and trace_clear_recursion() also require preemption disabled, we
can just merge the logical.
This patch will make sure the preemption has been disabled when
trace_test_and_set_recursion() return bit >= 0, and
trace_clear_recursion() will enable the preemption if previously
enabled.
Link: https://lkml.kernel.org/r/13bde807-779c-aa4c-0672-20515ae365ea@linux.alibaba.com
CC: Petr Mladek <pmladek@suse.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jisheng Zhang <jszhang@kernel.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Miroslav Benes <mbenes@suse.cz>
Reported-by: Abaci <abaci@linux.alibaba.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com>
[ Removed extra line in comment - SDR ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Make sure to prod idle CPUs so they call klp_update_patch_state().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Vasily Gorbik <gor@linux.ibm.com> # on s390
Link: https://lkml.kernel.org/r/20210929151723.162004989@infradead.org
Instead of frobbing around with scheduler internals, use the shiny new
task_call_func() interface.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Vasily Gorbik <gor@linux.ibm.com> # on s390
Link: https://lkml.kernel.org/r/20210929152428.709906138@infradead.org
The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().
Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Merge tag 'livepatching-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching update from Petr Mladek:
- Use TIF_NOTIFY_SIGNAL infrastructure instead of the fake signal
* tag 'livepatching-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
livepatch: Replace the fake signal sending with TIF_NOTIFY_SIGNAL infrastructure
Livepatch sends a fake signal to all remaining blocking tasks of a
running transition after a set period of time. It uses TIF_SIGPENDING
flag for the purpose. Commit 12db8b6900 ("entry: Add support for
TIF_NOTIFY_SIGNAL") added a generic infrastructure to achieve the same.
Replace our bespoke solution with the generic one.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller. Note that this slightly changes the
behavior for the livepatch code in that the symbols from vmlinux are not
iterated anymore if objname is set, but that actually is the desired
behavior in this case.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Allow for a RCU-sched critical section around find_module, following
the lower level find_module_all helper, and switch the two callers
outside of module.c to use such a RCU-sched critical section instead
of module_mutex.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, the ftrace call
will be able to set the ip of the calling function. This will improve the
performance of live kernel patching where it does not need all the regs to
be stored just to change the instruction pointer.
If all archs that support live kernel patching also support
HAVE_DYNAMIC_FTRACE_WITH_ARGS, then the architecture specific function
klp_arch_set_pc() could be made generic.
It is possible that an arch can support HAVE_DYNAMIC_FTRACE_WITH_ARGS but
not HAVE_DYNAMIC_FTRACE_WITH_REGS and then have access to live patching.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: live-patching@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.
For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.
This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This adds CONFIG_FTRACE_RECORD_RECURSION that will record to a file
"recursed_functions" all the functions that caused recursion while a
callback to the function tracer was running.
Link: https://lkml.kernel.org/r/20201106023548.102375687@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: live-patching@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
If for some reason a function is called that triggers the recursion
detection of live patching, trigger a warning. By not executing the live
patch code, it is possible that the old unpatched function will be called
placing the system into an unknown state.
Link: https://lore.kernel.org/r/20201029145709.GD16774@alley
Link: https://lkml.kernel.org/r/20201106023547.312639435@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org
Suggested-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.
The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.
Link: https://lkml.kernel.org/r/20201028115613.291169246@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.122802424@goodmis.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Fix multiple occurrences of duplicated words in kernel/.
Fix one typo/spello on the same line as a duplicate word. Change one
instance of "the the" to "that the". Otherwise just drop one of the
repeated words.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the following sparse warning:
kernel/livepatch/core.c:748:5: warning: symbol 'klp_apply_object_relocs' was
not declared.
The klp_apply_object_relocs() has only one call site within core.c;
it should be static
Fixes: 7c8e2bdd5f ("livepatch: Apply vmlinux-specific KLP relocations early")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Samuel Zou <zou_wei@huawei.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Now that the livepatch code no longer needs the text_mutex for changing
module permissions, move its usage down to apply_relocate_add().
Note the s390 version of apply_relocate_add() doesn't need to use the
text_mutex because it already uses s390_kernel_write_lock, which
accomplishes the same task.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
With arch_klp_init_object_loaded() gone, and apply_relocate_add() now
using text_poke(), livepatch no longer needs to use module_disable_ro().
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Prevent module-specific KLP rela sections from referencing vmlinux
symbols. This helps prevent ordering issues with module special section
initializations. Presumably such symbols are exported and normal relas
can be used instead.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
After the previous patch, vmlinux-specific KLP relocations are now
applied early during KLP module load. This means that .klp.arch
sections are no longer needed for *vmlinux-specific* KLP relocations.
One might think they're still needed for *module-specific* KLP
relocations. If a to-be-patched module is loaded *after* its
corresponding KLP module is loaded, any corresponding KLP relocations
will be delayed until the to-be-patched module is loaded. If any
special sections (.parainstructions, for example) rely on those
relocations, their initializations (apply_paravirt) need to be done
afterwards. Thus the apparent need for arch_klp_init_object_loaded()
and its corresponding .klp.arch sections -- it allows some of the
special section initializations to be done at a later time.
But... if you look closer, that dependency between the special sections
and the module-specific KLP relocations doesn't actually exist in
reality. Looking at the contents of the .altinstructions and
.parainstructions sections, there's not a realistic scenario in which a
KLP module's .altinstructions or .parainstructions section needs to
access a symbol in a to-be-patched module. It might need to access a
local symbol or even a vmlinux symbol; but not another module's symbol.
When a special section needs to reference a local or vmlinux symbol, a
normal rela can be used instead of a KLP rela.
Since the special section initializations don't actually have any real
dependency on module-specific KLP relocations, .klp.arch and
arch_klp_init_object_loaded() no longer have a reason to exist. So
remove them.
As Peter said much more succinctly:
So the reason for .klp.arch was that .klp.rela.* stuff would overwrite
paravirt instructions. If that happens you're doing it wrong. Those
RELAs are core kernel, not module, and thus should've happened in
.rela.* sections at patch-module loading time.
Reverting this removes the two apply_{paravirt,alternatives}() calls
from the late patching path, and means we don't have to worry about
them when removing module_disable_ro().
[ jpoimboe: Rewrote patch description. Tweaked klp_init_object_loaded()
error path. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
KLP relocations are livepatch-specific relocations which are applied to
a KLP module's text or data. They exist for two reasons:
1) Unexported symbols: replacement functions often need to access
unexported symbols (e.g. static functions), which "normal"
relocations don't allow.
2) Late module patching: this is the ability for a KLP module to
bypass normal module dependencies, such that the KLP module can be
loaded *before* a to-be-patched module. This means that
relocations which need to access symbols in the to-be-patched
module might need to be applied to the KLP module well after it has
been loaded.
Non-late-patched KLP relocations are applied from the KLP module's init
function. That usually works fine, unless the patched code wants to use
alternatives, paravirt patching, jump tables, or some other special
section which needs relocations. Then we run into ordering issues and
crashes.
In order for those special sections to work properly, the KLP
relocations should be applied *before* the special section init code
runs, such as apply_paravirt(), apply_alternatives(), or
jump_label_apply_nops().
You might think the obvious solution would be to move the KLP relocation
initialization earlier, but it's not necessarily that simple. The
problem is the above-mentioned late module patching, for which KLP
relocations can get applied well after the KLP module is loaded.
To "fix" this issue in the past, we created .klp.arch sections:
.klp.arch.{module}..altinstructions
.klp.arch.{module}..parainstructions
Those sections allow KLP late module patching code to call
apply_paravirt() and apply_alternatives() after the module-specific KLP
relocations (.klp.rela.{module}.{section}) have been applied.
But that has a lot of drawbacks, including code complexity, the need for
arch-specific code, and the (per-arch) danger that we missed some
special section -- for example the __jump_table section which is used
for jump labels.
It turns out there's a simpler and more functional approach. There are
two kinds of KLP relocation sections:
1) vmlinux-specific KLP relocation sections
.klp.rela.vmlinux.{sec}
These are relocations (applied to the KLP module) which reference
unexported vmlinux symbols.
2) module-specific KLP relocation sections
.klp.rela.{module}.{sec}:
These are relocations (applied to the KLP module) which reference
unexported or exported module symbols.
Up until now, these have been treated the same. However, they're
inherently different.
Because of late module patching, module-specific KLP relocations can be
applied very late, thus they can create the ordering headaches described
above.
But vmlinux-specific KLP relocations don't have that problem. There's
nothing to prevent them from being applied earlier. So apply them at
the same time as normal relocations, when the KLP module is being
loaded.
This means that for vmlinux-specific KLP relocations, we no longer have
any ordering issues. vmlinux-referencing jump labels, alternatives, and
paravirt patching will work automatically, without the need for the
.klp.arch hacks.
All that said, for module-specific KLP relocations, the ordering
problems still exist and we *do* still need .klp.arch. Or do we? Stay
tuned.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This is purely a theoretical issue, but if there were a module named
vmlinux.ko, the livepatch relocation code wouldn't be able to
distinguish between vmlinux-specific and vmlinux.o-specific KLP
relocations.
If CONFIG_LIVEPATCH is enabled, don't allow a module named vmlinux.ko.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
- PERAMAENT flag to ftrace_ops when attaching a callback to a function
As /proc/sys/kernel/ftrace_enabled when set to zero will disable all
attached callbacks in ftrace, this has a detrimental impact on live
kernel tracing, as it disables all that it patched. If a ftrace_ops
is registered to ftrace with the PERMANENT flag set, it will prevent
ftrace_enabled from being disabled, and if ftrace_enabled is already
disabled, it will prevent a ftrace_ops with PREMANENT flag set from
being registered.
- New register_ftrace_direct(). As eBPF would like to register its own
trampolines to be called by the ftrace nop locations directly,
without going through the ftrace trampoline, this function has been
added. This allows for eBPF trampolines to live along side of
ftrace, perf, kprobe and live patching. It also utilizes the ftrace
enabled_functions file that keeps track of functions that have been
modified in the kernel, to allow for security auditing.
- Allow for kernel internal use of ftrace instances. Subsystems in
the kernel can now create and destroy their own tracing instances
which allows them to have their own tracing buffer, and be able
to record events without worrying about other users from writing over
their data.
- New seq_buf_hex_dump() that lets users use the hex_dump() in their
seq_buf usage.
- Notifications now added to tracing_max_latency to allow user space
to know when a new max latency is hit by one of the latency tracers.
- Wider spread use of generic compare operations for use of bsearch and
friends.
- More synthetic event fields may be defined (32 up from 16)
- Use of xarray for architectures with sparse system calls, for the
system call trace events.
This along with small clean ups and fixes.
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Merge tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New tracing features:
- New PERMANENT flag to ftrace_ops when attaching a callback to a
function.
As /proc/sys/kernel/ftrace_enabled when set to zero will disable
all attached callbacks in ftrace, this has a detrimental impact on
live kernel tracing, as it disables all that it patched. If a
ftrace_ops is registered to ftrace with the PERMANENT flag set, it
will prevent ftrace_enabled from being disabled, and if
ftrace_enabled is already disabled, it will prevent a ftrace_ops
with PREMANENT flag set from being registered.
- New register_ftrace_direct().
As eBPF would like to register its own trampolines to be called by
the ftrace nop locations directly, without going through the ftrace
trampoline, this function has been added. This allows for eBPF
trampolines to live along side of ftrace, perf, kprobe and live
patching. It also utilizes the ftrace enabled_functions file that
keeps track of functions that have been modified in the kernel, to
allow for security auditing.
- Allow for kernel internal use of ftrace instances.
Subsystems in the kernel can now create and destroy their own
tracing instances which allows them to have their own tracing
buffer, and be able to record events without worrying about other
users from writing over their data.
- New seq_buf_hex_dump() that lets users use the hex_dump() in their
seq_buf usage.
- Notifications now added to tracing_max_latency to allow user space
to know when a new max latency is hit by one of the latency
tracers.
- Wider spread use of generic compare operations for use of bsearch
and friends.
- More synthetic event fields may be defined (32 up from 16)
- Use of xarray for architectures with sparse system calls, for the
system call trace events.
This along with small clean ups and fixes"
* tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (51 commits)
tracing: Enable syscall optimization for MIPS
tracing: Use xarray for syscall trace events
tracing: Sample module to demonstrate kernel access to Ftrace instances.
tracing: Adding new functions for kernel access to Ftrace instances
tracing: Fix Kconfig indentation
ring-buffer: Fix typos in function ring_buffer_producer
ftrace: Use BIT() macro
ftrace: Return ENOTSUPP when DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not configured
ftrace: Rename ftrace_graph_stub to ftrace_stub_graph
ftrace: Add a helper function to modify_ftrace_direct() to allow arch optimization
ftrace: Add helper find_direct_entry() to consolidate code
ftrace: Add another check for match in register_ftrace_direct()
ftrace: Fix accounting bug with direct->count in register_ftrace_direct()
ftrace/selftests: Fix spelling mistake "wakeing" -> "waking"
tracing: Increase SYNTH_FIELDS_MAX for synthetic_events
ftrace/samples: Add a sample module that implements modify_ftrace_direct()
ftrace: Add modify_ftrace_direct()
tracing: Add missing "inline" in stub function of latency_fsnotify()
tracing: Remove stray tab in TRACE_EVAL_MAP_FILE's help text
tracing: Use seq_buf_hex_dump() to dump buffers
...
Livepatch uses ftrace for redirection to new patched functions. It means
that if ftrace is disabled, all live patched functions are disabled as
well. Toggling global 'ftrace_enabled' sysctl thus affect it directly.
It is not a problem per se, because only administrator can set sysctl
values, but it still may be surprising.
Introduce PERMANENT ftrace_ops flag to amend this. If the
FTRACE_OPS_FL_PERMANENT is set on any ftrace ops, the tracing cannot be
disabled by disabling ftrace_enabled. Equally, a callback with the flag
set cannot be registered if ftrace_enabled is disabled.
Link: http://lkml.kernel.org/r/20191016113316.13415-2-mbenes@suse.cz
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The atomic replace runs pre/post (un)install callbacks only from the new
livepatch. There are several reasons for this:
+ Simplicity: clear ordering of operations, no interactions between
old and new callbacks.
+ Reliability: only new livepatch knows what changes can already be made
by older livepatches and how to take over the state.
+ Testing: the atomic replace can be properly tested only when a newer
livepatch is available. It might be too late to fix unwanted effect
of callbacks from older livepatches.
It might happen that an older change is not enough and the same system
state has to be modified another way. Different changes need to get
distinguished by a version number added to struct klp_state.
The version can also be used to prevent loading incompatible livepatches.
The check is done when the livepatch is enabled. The rules are:
+ Any completely new system state modification is allowed.
+ System state modifications with the same or higher version are allowed
for already modified system states.
+ Cumulative livepatches must handle all system state modifications from
already installed livepatches.
+ Non-cumulative livepatches are allowed to touch already modified
system states.
Link: http://lkml.kernel.org/r/20191030154313.13263-4-pmladek@suse.com
To: Jiri Kosina <jikos@kernel.org>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
This is another step how to help maintaining more livepatches.
One big help was the atomic replace and cumulative livepatches. These
livepatches replace the already installed ones. Therefore it should
be enough when each cumulative livepatch is consistent.
The problems might come with shadow variables and callbacks. They might
change the system behavior or state so that it is no longer safe to
go back and use an older livepatch or the original kernel code. Also,
a new livepatch must be able to detect changes which were made by
the already installed livepatches.
This is where the livepatch system state tracking gets useful. It
allows to:
- find whether a system state has already been modified by
previous livepatches
- store data needed to manipulate and restore the system state
The information about the manipulated system states is stored in an
array of struct klp_state. It can be searched by two new functions
klp_get_state() and klp_get_prev_state().
The dependencies are going to be solved by a version field added later.
The only important information is that it will be allowed to modify
the same state by more non-cumulative livepatches. It is similar
to allowing to modify the same function several times. The livepatch
author is responsible for preventing incompatible changes.
Link: http://lkml.kernel.org/r/20191030154313.13263-3-pmladek@suse.com
To: Jiri Kosina <jikos@kernel.org>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pre/post (un)patch callbacks might manipulate the system state. Cumulative
livepatches might need to take over the changes made by the replaced
ones. For this they might need to access some data stored or referenced
by the old livepatches.
Therefore the replaced livepatches have to stay around until post_patch()
callback is called. It is achieved by calling the free functions later.
It is the same location where disabled livepatches have already been
freed.
Link: http://lkml.kernel.org/r/20191030154313.13263-2-pmladek@suse.com
To: Jiri Kosina <jikos@kernel.org>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
klp_module_coming() is called for every module appearing in the system.
It sets obj->mod to a patched module for klp_object obj. Unfortunately
it leaves it set even if an error happens later in the function and the
patched module is not allowed to be loaded.
klp_is_object_loaded() uses obj->mod variable and could currently give a
wrong return value. The bug is probably harmless as of now.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull livepatching updates from Jiri Kosina:
- stacktrace handling improvements from Miroslav benes
- debug output improvements from Petr Mladek
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
livepatch: Remove duplicate warning about missing reliable stacktrace support
Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()"
stacktrace: Remove weak version of save_stack_trace_tsk_reliable()
livepatch: Use static buffer for debugging messages under rq lock
livepatch: Remove stale kobj_added entries from kernel-doc descriptions
WARN_ON_ONCE() could not be called safely under rq lock because
of console deadlock issues. Moreover WARN_ON_ONCE() is superfluous in
klp_check_stack(), because stack_trace_save_tsk_reliable() cannot return
-ENOSYS thanks to klp_have_reliable_stack() check in
klp_try_switch_task().
[ mbenes: changelog edited ]
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
This reverts commit 1d98a69e5c. Commit
31adf2308f ("livepatch: Convert error about unsupported reliable
stacktrace into a warning") weakened the enforcement for architectures
to have reliable stack traces support. The system only warns now about
it.
It only makes sense to reintroduce the compile time checking in
klp_try_switch_task() again and bail out early.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
- Out of range read of stack trace output
- Fix for NULL pointer dereference in trace_uprobe_create()
- Fix to a livepatching / ftrace permission race in the module code
- Fix for NULL pointer dereference in free_ftrace_func_mapper()
- A couple of build warning clean ups
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Merge tag 'trace-v5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Out of range read of stack trace output
- Fix for NULL pointer dereference in trace_uprobe_create()
- Fix to a livepatching / ftrace permission race in the module code
- Fix for NULL pointer dereference in free_ftrace_func_mapper()
- A couple of build warning clean ups
* tag 'trace-v5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix NULL pointer dereference in free_ftrace_func_mapper()
module: Fix livepatch/ftrace module text permissions race
tracing/uprobe: Fix obsolete comment on trace_uprobe_create()
tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()
tracing: Make two symbols static
tracing: avoid build warning with HAVE_NOP_MCOUNT
tracing: Fix out-of-range read in trace_stack_print()
The err_buf array uses 128 bytes of stack space. Move it off the stack
by making it static. It's safe to use a shared buffer because
klp_try_switch_task() is called under klp_mutex.
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not see http www gnu org licenses
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details [based]
[from] [clk] [highbank] [c] you should have received a copy of the
gnu general public license along with this program if not see http
www gnu org licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 355 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Removing of non-DYNAMIC_FTRACE from 32bit x86
- Removing of mcount support from x86
- Emulating a call from int3 on x86_64, fixes live kernel patching
- Consolidated Tracing Error logs file
Minor updates:
- Removal of klp_check_compiler_support()
- kdb ftrace dumping output changes
- Accessing and creating ftrace instances from inside the kernel
- Clean up of #define if macro
- Introduction of TRACE_EVENT_NOP() to disable trace events based on config
options
And other minor fixes and clean ups
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Merge tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The major changes in this tracing update includes:
- Removal of non-DYNAMIC_FTRACE from 32bit x86
- Removal of mcount support from x86
- Emulating a call from int3 on x86_64, fixes live kernel patching
- Consolidated Tracing Error logs file
Minor updates:
- Removal of klp_check_compiler_support()
- kdb ftrace dumping output changes
- Accessing and creating ftrace instances from inside the kernel
- Clean up of #define if macro
- Introduction of TRACE_EVENT_NOP() to disable trace events based on
config options
And other minor fixes and clean ups"
* tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
x86: Hide the int3_emulate_call/jmp functions from UML
livepatch: Remove klp_check_compiler_support()
ftrace/x86: Remove mcount support
ftrace/x86_32: Remove support for non DYNAMIC_FTRACE
tracing: Simplify "if" macro code
tracing: Fix documentation about disabling options using trace_options
tracing: Replace kzalloc with kcalloc
tracing: Fix partial reading of trace event's id file
tracing: Allow RCU to run between postponed startup tests
tracing: Fix white space issues in parse_pred() function
tracing: Eliminate const char[] auto variables
ring-buffer: Fix mispelling of Calculate
tracing: probeevent: Fix to make the type of $comm string
tracing: probeevent: Do not accumulate on ret variable
tracing: uprobes: Re-enable $comm support for uprobe events
ftrace/x86_64: Emulate call function while updating in breakpoint handler
x86_64: Allow breakpoints to emulate call instructions
x86_64: Add gap to int3 to allow for call emulation
tracing: kdb: Allow ftdump to skip all but the last few entries
tracing: Add trace_total_entries() / trace_total_entries_cpu()
...
The only purpose of klp_check_compiler_support() is to make sure that we
are not using ftrace on x86 via mcount (because that's executed only after
prologue has already happened, and that's too late for livepatching
purposes).
Now that mcount is not supported by ftrace any more, there is no need for
klp_check_compiler_support() either.
Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1905102346100.17054@cbobk.fhfr.pm
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Here is the "big" set of driver core patches for 5.2-rc1
There are a number of ACPI patches in here as well, as Rafael said they
should go through this tree due to the driver core changes they
required. They have all been acked by the ACPI developers.
There are also a number of small subsystem-specific changes in here, due
to some changes to the kobject core code. Those too have all been acked
by the various subsystem maintainers.
As for content, it's pretty boring outside of the ACPI changes:
- spdx cleanups
- kobject documentation updates
- default attribute groups for kobjects
- other minor kobject/driver core fixes
All have been in linux-next for a while with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core/kobject updates from Greg KH:
"Here is the "big" set of driver core patches for 5.2-rc1
There are a number of ACPI patches in here as well, as Rafael said
they should go through this tree due to the driver core changes they
required. They have all been acked by the ACPI developers.
There are also a number of small subsystem-specific changes in here,
due to some changes to the kobject core code. Those too have all been
acked by the various subsystem maintainers.
As for content, it's pretty boring outside of the ACPI changes:
- spdx cleanups
- kobject documentation updates
- default attribute groups for kobjects
- other minor kobject/driver core fixes
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (47 commits)
kobject: clean up the kobject add documentation a bit more
kobject: Fix kernel-doc comment first line
kobject: Remove docstring reference to kset
firmware_loader: Fix a typo ("syfs" -> "sysfs")
kobject: fix dereference before null check on kobj
Revert "driver core: platform: Fix the usage of platform device name(pdev->name)"
init/config: Do not select BUILD_BIN2C for IKCONFIG
Provide in-kernel headers to make extending kernel easier
kobject: Improve doc clarity kobject_init_and_add()
kobject: Improve docs for kobject_add/del
driver core: platform: Fix the usage of platform device name(pdev->name)
livepatch: Replace klp_ktype_patch's default_attrs with groups
cpufreq: schedutil: Replace default_attrs field with groups
padata: Replace padata_attr_type default_attrs field with groups
irqdesc: Replace irq_kobj_type's default_attrs field with groups
net-sysfs: Replace ktype default_attrs field with groups
block: Replace all ktype default_attrs with groups
samples/kobject: Replace foo_ktype's default_attrs field with groups
kobject: Add support for default attribute groups to kobj_type
driver core: Postpone DMA tear-down until after devres release for probe failure
...
Pull livepatching updates from Jiri Kosina:
- livepatching kselftests improvements from Joe Lawrence and Miroslav
Benes
- making use of gcc's -flive-patching option when available, from
Miroslav Benes
- kobject handling cleanups, from Petr Mladek
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
livepatch: Remove duplicated code for early initialization
livepatch: Remove custom kobject state handling
livepatch: Convert error about unsupported reliable stacktrace into a warning
selftests/livepatch: Add functions.sh to TEST_PROGS_EXTENDED
kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled
selftests/livepatch: use TEST_PROGS for test scripts
kobject_init() call added one more operation that has to be
done when doing the early initialization of both static and
dynamic livepatch structures.
It would have been easier when the early initialization code
was not duplicated. Let's deduplicate it for future generations
of livepatching hackers.
The patch does not change the existing behavior.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
kobject_init() always succeeds and sets the reference count to 1.
It allows to always free the structures via kobject_put() and
the related release callback.
Note that the custom kobject state handling was used only
because we did not know that kobject_put() can and actually
should get called even when kobject_init_and_add() fails.
The patch should not change the existing behavior.
Suggested-by: "Tobin C. Harding" <tobin@kernel.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The commit d0807da78e ("livepatch: Remove immediate feature") caused
that any livepatch was refused when reliable stacktraces were not supported
on the given architecture.
The limitation is too strong. User space processes are safely migrated
even when entering or leaving the kernel. Kthreads transition would
need to get forced. But it is safe when:
+ The livepatch does not change the semantic of the code.
+ Callbacks do not depend on a safely finished transition.
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The kobj_type default_attrs field is being replaced by the
default_groups field. Replace klp_ktype_patch's default_attrs field
with default_groups and use the ATTRIBUTE_GROUPS macro to create
klp_patch_groups.
This patch was tested by loading the livepatch-sample module and
verifying that the sysfs files for the attributes in the default groups
were created.
Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The atomic replace allows to create cumulative patches. They are useful when
you maintain many livepatches and want to remove one that is lower on the
stack. In addition it is very useful when more patches touch the same function
and there are dependencies between them.
It's also a feature some of the distros are using already to distribute
their patches.
Linus Torvalds