The latest merge of the tracing tree sorts the mcount table at build time.
But s390 appears to do things differently (like always) and replaces the
sorted table back to the original unsorted one. As the ftrace algorithm
depends on it being sorted, bad things happen when it is not, and s390
experienced those bad things.
Add a new config to tell the boot if the mcount table is sorted or not,
and allow s390 to opt out of it.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYezl+RQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qs5wAQCO2K1uB+XI4rown8zKLrGxOiFIXChi
Ds5GKJwYlcOnwQEAqKK3mAodmMy6ydbeY1OY1IDdTkOCAd752FDIe1Qozws=
=aF8W
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"Fix s390 breakage from sorting mcount tables.
The latest merge of the tracing tree sorts the mcount table at build
time. But s390 appears to do things differently (like always) and
replaces the sorted table back to the original unsorted one. As the
ftrace algorithm depends on it being sorted, bad things happen when it
is not, and s390 experienced those bad things.
Add a new config to tell the boot if the mcount table is sorted or
not, and allow s390 to opt out of it"
* tag 'trace-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix assuming build time sort works for s390
To speed up the boot process, as mcount_loc needs to be sorted for ftrace
to work properly, sorting it at build time is more efficient than boot up
and can save milliseconds of time. Unfortunately, this change broke s390
as it will modify the mcount_loc location after the sorting takes place
and will put back the unsorted locations. Since the sorting is skipped at
boot up if it is believed that it was sorted at run time, ftrace can crash
as its algorithms are dependent on the list being sorted.
Add a new config BUILDTIME_MCOUNT_SORT that is set when
BUILDTIME_TABLE_SORT but not if S390 is set. Use this config to determine
if sorting should take place at boot up.
Link: https://lore.kernel.org/all/yt9dee51ctfn.fsf@linux.ibm.com/
Fixes: 72b3942a17 ("scripts: ftrace - move the sort-processing in ftrace_init")
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
New:
- The Real Time Linux Analysis (RTLA) tool is added to the tools directory.
- Can safely filter on user space pointers with: field.ustring ~ "match-string"
- eprobes can now be filtered like any other event.
- trace_marker(_raw) now uses stream_open() to allow multiple threads to safely
write to it. Note, this could possibly break existing user space, but we will
not know until we hear about it, and then can revert the change if need be.
- New field in events to display when bottom halfs are disabled.
- Sorting of the ftrace functions are now done at compile time instead of
at bootup.
Infrastructure changes to support future efforts:
- Added __rel_loc type for trace events. Similar to __data_loc but the offset
to the dynamic data is based off of the location of the descriptor and not
the beginning of the event. Needed for user defined events.
- Some simplification of event trigger code.
- Make synthetic events process its callback better to not hinder other
event callbacks that are registered. Needed for user defined events.
And other small fixes and clean ups.
-
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYeGvcxQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qrZtAP9ICjJxX54MTErElhhUL/NFLV7wqhJi
OIAgmp6jGVRqPAD+JxQtBnGH+3XMd71ioQkTfQ1rp+jBz2ERBj2DmELUAg0=
=zmda
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New:
- The Real Time Linux Analysis (RTLA) tool is added to the tools
directory.
- Can safely filter on user space pointers with: field.ustring ~
"match-string"
- eprobes can now be filtered like any other event.
- trace_marker(_raw) now uses stream_open() to allow multiple threads
to safely write to it. Note, this could possibly break existing
user space, but we will not know until we hear about it, and then
can revert the change if need be.
- New field in events to display when bottom halfs are disabled.
- Sorting of the ftrace functions are now done at compile time
instead of at bootup.
Infrastructure changes to support future efforts:
- Added __rel_loc type for trace events. Similar to __data_loc but
the offset to the dynamic data is based off of the location of the
descriptor and not the beginning of the event. Needed for user
defined events.
- Some simplification of event trigger code.
- Make synthetic events process its callback better to not hinder
other event callbacks that are registered. Needed for user defined
events.
And other small fixes and cleanups"
* tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits)
tracing: Add ustring operation to filtering string pointers
rtla: Add rtla timerlat hist documentation
rtla: Add rtla timerlat top documentation
rtla: Add rtla timerlat documentation
rtla: Add rtla osnoise hist documentation
rtla: Add rtla osnoise top documentation
rtla: Add rtla osnoise man page
rtla: Add Documentation
rtla/timerlat: Add timerlat hist mode
rtla: Add timerlat tool and timelart top mode
rtla/osnoise: Add the hist mode
rtla/osnoise: Add osnoise top mode
rtla: Add osnoise tool
rtla: Helper functions for rtla
rtla: Real-Time Linux Analysis tool
tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails
tracing: Remove duplicate warnings when calling trace_create_file()
tracing/kprobes: 'nmissed' not showed correctly for kretprobe
tracing: Add test for user space strings when filtering on string pointers
tracing: Have syscall trace events use trace_event_buffer_lock_reserve()
...
Now that ftrace function pointers are sorted at compile time, add a test
that makes sure they are sorted at run time. This test is only run if it is
configured in.
Link: https://lkml.kernel.org/r/20211206151858.4d21a24d@gandalf.local.home
Cc: Yinan Liu <yinan@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When the kernel starts, the initialization of ftrace takes
up a portion of the time (approximately 6~8ms) to sort mcount
addresses. We can save this time by moving mcount-sorting to
compile time.
Link: https://lkml.kernel.org/r/20211212113358.34208-2-yinan@linux.alibaba.com
Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Adding ops cleanup to unregister_ftrace_direct_multi,
so it can be reused in another register call.
Link: https://lkml.kernel.org/r/20211206182032.87248-3-jolsa@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Fixes: f64dd4627e ("ftrace: Add multi direct register/unregister interface")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Now when we have *direct_multi interface the direct_functions
hash is no longer owned just by direct_ops. It's also used by
any other ftrace_ops passed to *direct_multi interface.
Thus to find out that we are unregistering the last function
from direct_ops, we need to check directly direct_ops's hash.
Link: https://lkml.kernel.org/r/20211206182032.87248-2-jolsa@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Fixes: f64dd4627e ("ftrace: Add multi direct register/unregister interface")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
We can't call unregister_ftrace_function under ftrace_lock.
Link: https://lkml.kernel.org/r/20211109114217.1645296-1-jolsa@kernel.org
Fixes: ed29271894 ("ftrace/direct: Do not disable when switching direct callers")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Merge more updates from Andrew Morton:
"87 patches.
Subsystems affected by this patch series: mm (pagecache and hugetlb),
procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs,
init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork,
sysvfs, kcov, gdb, resource, selftests, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits)
ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL
ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
selftests/kselftest/runner/run_one(): allow running non-executable files
virtio-mem: disallow mapping virtio-mem memory via /dev/mem
kernel/resource: disallow access to exclusive system RAM regions
kernel/resource: clean up and optimize iomem_is_exclusive()
scripts/gdb: handle split debug for vmlinux
kcov: replace local_irq_save() with a local_lock_t
kcov: avoid enable+disable interrupts if !in_task()
kcov: allocate per-CPU memory on the relevant node
Documentation/kcov: define `ip' in the example
Documentation/kcov: include types.h in the example
sysv: use BUILD_BUG_ON instead of runtime check
kernel/fork.c: unshare(): use swap() to make code cleaner
seq_file: fix passing wrong private data
seq_file: move seq_escape() to a header
signal: remove duplicate include in signal.h
crash_dump: remove duplicate include in crash_dump.h
crash_dump: fix boolreturn.cocci warning
hfs/hfsplus: use WARN_ON for sanity check
...
Move core_kernel_data() into sections.h and rename it to
is_kernel_core_data(), also make it return bool value, then update all the
callers.
Link: https://lkml.kernel.org/r/20210930071143.63410-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- 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.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYYBdxhQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qp1sAQD2oYFwaG3sx872gj/myBcHIBSKdiki
Hry5csd8zYDBpgD+Poylopt5JIbeDuoYw/BedgEXmscZ8Qr7VzjAXdnv/Q4=
=Loz8
-----END PGP SIGNATURE-----
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
...
Some functions had kernel-doc that used a comma instead of a hash to
separate the function name from the one line description.
Also, the "ftrace_is_dead()" had an incomplete description.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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>
This symbol is not used outside of ftrace.c, so marks it static.
Fixes the following sparse warning:
kernel/trace/ftrace.c:579:5: warning: symbol 'ftrace_profile_pages_init'
was not declared. Should it be static?
Link: https://lkml.kernel.org/r/1634640534-18280-1-git-send-email-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Fixes: cafb168a1c ("tracing: make the function profiler per cpu")
Signed-off-by: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently to switch a set of "multi" direct trampolines from one
trampoline to another, a full shutdown of the current set needs to be
done, followed by an update to what trampoline the direct callers would
call, and then re-enabling the callers. This leaves a time when the
functions will not be calling anything, and events may be missed.
Instead, use a trick to allow all the functions with direct trampolines
attached will always call either the new or old trampoline while the
switch is happening. To do this, first attach a "dummy" callback via
ftrace to all the functions that the current direct trampoline is attached
to. This will cause the functions to call the "list func" instead of the
direct trampoline. The list function will call the direct trampoline
"helper" that will set the function it should call as it returns back to
the ftrace trampoline.
At this moment, the direct caller descriptor can safely update the direct
call trampoline. The list function will pick either the new or old
function (depending on the memory coherency model of the architecture).
Now removing the dummy function from each of the locations of the direct
trampoline caller, will put back the direct call, but now to the new
trampoline.
A better visual is:
[ Changing direct call from my_direct_1 to my_direct_2 ]
<traced_func>:
call my_direct_1
||||||||||||||||||||
vvvvvvvvvvvvvvvvvvvv
<traced_func>:
call ftrace_caller
<ftrace_caller>:
[..]
call ftrace_ops_list_func
ftrace_ops_list_func()
{
ops->func() -> direct_helper -> set rax to my_direct_1 or my_direct_2
}
call rax (to either my_direct_1 or my_direct_2
||||||||||||||||||||
vvvvvvvvvvvvvvvvvvvv
<traced_func>:
call my_direct_2
Link: https://lore.kernel.org/all/20211014162819.5c85618b@gandalf.local.home/
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Adding interface to modify registered direct function
for ftrace_ops. Adding following function:
modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
The function changes the currently registered direct
function for all attached functions.
Link: https://lkml.kernel.org/r/20211008091336.33616-8-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Adding interface to register multiple direct functions
within single call. Adding following functions:
register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
The register_ftrace_direct_multi registers direct function (addr)
with all functions in ops filter. The ops filter can be updated
before with ftrace_set_filter_ip calls.
All requested functions must not have direct function currently
registered, otherwise register_ftrace_direct_multi will fail.
The unregister_ftrace_direct_multi unregisters ops related direct
functions.
Link: https://lkml.kernel.org/r/20211008091336.33616-7-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Factor out the code that adds (ip, addr) tuple to direct_functions
hash in new ftrace_add_rec_direct function. It will be used in
following patches.
Link: https://lkml.kernel.org/r/20211008091336.33616-6-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In an effort to enable -Wcast-function-type in the top-level Makefile to
support Control Flow Integrity builds, all function casts need to be
removed.
This means that ftrace_ops_list_func() can no longer be defined as
ftrace_ops_no_ops(). The reason for ftrace_ops_no_ops() is to use that when
an architecture calls ftrace_ops_list_func() with only two parameters
(called from assembly). And to make sure there's no C side-effects, those
archs call ftrace_ops_no_ops() which only has two parameters, as
ftrace_ops_list_func() has four parameters.
Instead of a typecast, use vmlinux.lds.h to define ftrace_ops_list_func() to
arch_ftrace_ops_list_func() that will define the proper set of parameters.
Link: https://lore.kernel.org/r/20200614070154.6039-1-oscar.carter@gmx.com
Link: https://lkml.kernel.org/r/20200617165616.52241bde@oasis.local.home
Link: https://lore.kernel.org/all/20211005053922.GA702049@embeddedor/
Requested-by: Oscar Carter <oscar.carter@gmx.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
While writing an email explaining the "bit = 0" logic for a discussion on
making ftrace_test_recursion_trylock() disable preemption, I discovered a
path that makes the "not do the logic if bit is zero" unsafe.
The recursion logic is done in hot paths like the function tracer. Thus,
any code executed causes noticeable overhead. Thus, tricks are done to try
to limit the amount of code executed. This included the recursion testing
logic.
Having recursion testing is important, as there are many paths that can
end up in an infinite recursion cycle when tracing every function in the
kernel. Thus protection is needed to prevent that from happening.
Because it is OK to recurse due to different running context levels (e.g.
an interrupt preempts a trace, and then a trace occurs in the interrupt
handler), a set of bits are used to know which context one is in (normal,
softirq, irq and NMI). If a recursion occurs in the same level, it is
prevented*.
Then there are infrastructure levels of recursion as well. When more than
one callback is attached to the same function to trace, it calls a loop
function to iterate over all the callbacks. Both the callbacks and the
loop function have recursion protection. The callbacks use the
"ftrace_test_recursion_trylock()" which has a "function" set of context
bits to test, and the loop function calls the internal
trace_test_and_set_recursion() directly, with an "internal" set of bits.
If an architecture does not implement all the features supported by ftrace
then the callbacks are never called directly, and the loop function is
called instead, which will implement the features of ftrace.
Since both the loop function and the callbacks do recursion protection, it
was seemed unnecessary to do it in both locations. Thus, a trick was made
to have the internal set of recursion bits at a more significant bit
location than the function bits. Then, if any of the higher bits were set,
the logic of the function bits could be skipped, as any new recursion
would first have to go through the loop function.
This is true for architectures that do not support all the ftrace
features, because all functions being traced must first go through the
loop function before going to the callbacks. But this is not true for
architectures that support all the ftrace features. That's because the
loop function could be called due to two callbacks attached to the same
function, but then a recursion function inside the callback could be
called that does not share any other callback, and it will be called
directly.
i.e.
traced_function_1: [ more than one callback tracing it ]
call loop_func
loop_func:
trace_recursion set internal bit
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
traced_function_2: [ only traced by above callback ]
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
[ wash, rinse, repeat, BOOM! out of shampoo! ]
Thus, the "bit == 0 skip" trick is not safe, unless the loop function is
call for all functions.
Since we want to encourage architectures to implement all ftrace features,
having them slow down due to this extra logic may encourage the
maintainers to update to the latest ftrace features. And because this
logic is only safe for them, remove it completely.
[*] There is on layer of recursion that is allowed, and that is to allow
for the transition between interrupt context (normal -> softirq ->
irq -> NMI), because a trace may occur before the context update is
visible to the trace recursion logic.
Link: https://lore.kernel.org/all/609b565a-ed6e-a1da-f025-166691b5d994@linux.alibaba.com/
Link: https://lkml.kernel.org/r/20211018154412.09fcad3c@gandalf.local.home
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>
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: Miroslav Benes <mbenes@suse.cz>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jisheng Zhang <jszhang@kernel.org>
Cc: =?utf-8?b?546L6LSH?= <yun.wang@linux.alibaba.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: stable@vger.kernel.org
Fixes: edc15cafcb ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Most of ARCHs use empty ftrace_dyn_arch_init(), introduce a weak common
ftrace_dyn_arch_init() to cleanup them.
Link: https://lkml.kernel.org/r/20210909090216.1955240-1-o451686892@gmail.com
Acked-by: Heiko Carstens <hca@linux.ibm.com> (s390)
Acked-by: Helge Deller <deller@gmx.de> (parisc)
Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When building the files in the tracefs file system, do not by default set
any permissions for OTH (other). This will make it easier for admins who
want to define a group for accessing tracefs and not having to first
disable all the permission bits for "other" in the file system.
As tracing can leak sensitive information, it should never by default
allowing all users access. An admin can still set the permission bits for
others to have access, which may be useful for creating a honeypot and
seeing who takes advantage of it and roots the machine.
Link: https://lkml.kernel.org/r/20210818153038.864149276@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Instead of having the logic that does trace_pid_list open coded, wrap it in
abstract functions. This will allow a rewrite of the logic that implements
the trace_pid_list without affecting the users.
Note, this causes a change in behavior. Every time a pid is written into
the set_*_pid file, it creates a new list and uses RCU to update it. If
pid_max is lowered, but there was a pid currently in the list that was
higher than pid_max, those pids will now be removed on updating the list.
The old behavior kept that from happening.
The rewrite of the pid_list logic will no longer depend on pid_max,
and will return the old behavior.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Implementing live patching on s390 requires each function's prologue to
contain a very special kind of nop, which gcc and clang don't generate.
However, the current code assumes that if CC_USING_NOP_MCOUNT is
defined, then whatever the compiler generates is good enough.
Move the CC_USING_NOP_MCOUNT check into the new ftrace_need_init_nop()
macro, that the architectures can override.
An alternative solution is to disable using -mnop-mcount in the
Makefile, however, this makes the build logic (even) more complicated
and forces the arch-specific code to deal with the useless __fentry__
symbol.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20210728212546.128248-2-iii@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The variable ret is being initialized with a value that is never
read, it is being updated later on. The assignment is redundant and
can be removed.
Link: https://lkml.kernel.org/r/20210721120915.122278-1-colin.king@canonical.com
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
synchronize_rcu_tasks_rude() triggers IPIs and forces rescheduling on
all CPUs. It is a costly operation and, when targeting nohz_full CPUs,
very disrupting (hence the name). So avoid calling it when 'old_hash'
doesn't need to be freed.
Link: https://lkml.kernel.org/r/20210721114726.1545103-1-nsaenzju@redhat.com
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Using list_move() instead of list_del() + list_add().
Link: https://lkml.kernel.org/r/20210608031108.2820996-1-libaokun1@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
It was reported that a bug on arm64 caused a bad ip address to be used for
updating into a nop in ftrace_init(), but the error path (rightfully)
returned -EINVAL and not -EFAULT, as the bug caused more than one error to
occur. But because -EINVAL was returned, the ftrace_bug() tried to report
what was at the location of the ip address, and read it directly. This
caused the machine to panic, as the ip was not pointing to a valid memory
address.
Instead, read the ip address with copy_from_kernel_nofault() to safely
access the memory, and if it faults, report that the address faulted,
otherwise report what was in that location.
Link: https://lore.kernel.org/lkml/20210607032329.28671-1-mark-pk.tsai@mediatek.com/
Cc: stable@vger.kernel.org
Fixes: 05736a427f ("ftrace: warn on failure to disable mcount callers")
Reported-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Now that there's a library that accesses the tracefs file system,
(libtracefs), the way the files are interacted with is slightly
different than the command line. For instance, the write() system
call is used directly instead of an echo. This exposes some old bugs.
If a probe is written to "set_ftrace_filter" without any white space
after it, it will be ignored. This is because the write expects
that a string written to it that does not end with white spaces thinks
there is more to come. But if the file is closed, the release function
needs to finish it. The "set_ftrace_filter" release function handles
the filter part of the "set_ftrace_filter" file, but did not handle
the probe part.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYJP4OBQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6quzjAQCoFQXkJtYhwlMk0dTxclrsQlm0t93H
pHwJA9Zyxe25UgD8D/rpG/wtHaSSuP6omEDbqvshpNdszqKb0Nt+UM116QU=
=niJ6
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"Fix probes written to the set_ftrace_filter file
Now that there's a library that accesses the tracefs file system
(libtracefs), the way the files are interacted with is slightly
different than the command line. For instance, the write() system call
is used directly instead of an echo. This exposes some old bugs.
If a probe is written to "set_ftrace_filter" without any white space
after it, it will be ignored. This is because the write expects that a
string written to it that does not end with white spaces thinks there
is more to come. But if the file is closed, the release function needs
to finish it. The "set_ftrace_filter" release function handles the
filter part of the "set_ftrace_filter" file, but did not handle the
probe part"
* tag 'trace-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Handle commands when closing set_ftrace_filter file
# echo switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter
will cause switch_mm to stop tracing by the traceoff command.
# echo -n switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter
does nothing.
The reason is that the parsing in the write function only processes
commands if it finished parsing (there is white space written after the
command). That's to handle:
write(fd, "switch_mm:", 10);
write(fd, "traceoff", 8);
cases, where the command is broken over multiple writes.
The problem is if the file descriptor is closed, then the write call is
not processed, and the command needs to be processed in the release code.
The release code can handle matching of functions, but does not handle
commands.
Cc: stable@vger.kernel.org
Fixes: eda1e32855 ("tracing: handle broken names in ftrace filter")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
New feature:
The "func-no-repeats" option in tracefs/options directory. When set
the function tracer will detect if the current function being traced
is the same as the previous one, and instead of recording it, it will
keep track of the number of times that the function is repeated in a row.
And when another function is recorded, it will write a new event that
shows the function that repeated, the number of times it repeated and
the time stamp of when the last repeated function occurred.
Enhancements:
In order to implement the above "func-no-repeats" option, the ring
buffer timestamp can now give the accurate timestamp of the event
as it is being recorded, instead of having to record an absolute
timestamp for all events. This helps the histogram code which no longer
needs to waste ring buffer space.
New validation logic to make sure all trace events that access
dereferenced pointers do so in a safe way, and will warn otherwise.
Fixes:
No longer limit the PIDs of tasks that are recorded for "saved_cmdlines"
to PID_MAX_DEFAULT (32768), as systemd now allows for a much larger
range. This caused the mapping of PIDs to the task names to be dropped
for all tasks with a PID greater than 32768.
Change trace_clock_global() to never block. This caused a deadlock.
Clean ups:
Typos, prototype fixes, and removing of duplicate or unused code.
Better management of ftrace_page allocations.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYI/1vBQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qiL0AP9EemIC5TDh2oihqLRNeUjdTu0ryEoM
HRFqxozSF985twD/bfkt86KQC8rLHwxTbxQZ863bmdaC6cMGFhWiF+H/MAs=
=psYt
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New feature:
- A new "func-no-repeats" option in tracefs/options directory.
When set the function tracer will detect if the current function
being traced is the same as the previous one, and instead of
recording it, it will keep track of the number of times that the
function is repeated in a row. And when another function is
recorded, it will write a new event that shows the function that
repeated, the number of times it repeated and the time stamp of
when the last repeated function occurred.
Enhancements:
- In order to implement the above "func-no-repeats" option, the ring
buffer timestamp can now give the accurate timestamp of the event
as it is being recorded, instead of having to record an absolute
timestamp for all events. This helps the histogram code which no
longer needs to waste ring buffer space.
- New validation logic to make sure all trace events that access
dereferenced pointers do so in a safe way, and will warn otherwise.
Fixes:
- No longer limit the PIDs of tasks that are recorded for
"saved_cmdlines" to PID_MAX_DEFAULT (32768), as systemd now allows
for a much larger range. This caused the mapping of PIDs to the
task names to be dropped for all tasks with a PID greater than
32768.
- Change trace_clock_global() to never block. This caused a deadlock.
Clean ups:
- Typos, prototype fixes, and removing of duplicate or unused code.
- Better management of ftrace_page allocations"
* tag 'trace-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (32 commits)
tracing: Restructure trace_clock_global() to never block
tracing: Map all PIDs to command lines
ftrace: Reuse the output of the function tracer for func_repeats
tracing: Add "func_no_repeats" option for function tracing
tracing: Unify the logic for function tracing options
tracing: Add method for recording "func_repeats" events
tracing: Add "last_func_repeats" to struct trace_array
tracing: Define new ftrace event "func_repeats"
tracing: Define static void trace_print_time()
ftrace: Simplify the calculation of page number for ftrace_page->records some more
ftrace: Store the order of pages allocated in ftrace_page
tracing: Remove unused argument from "ring_buffer_time_stamp()
tracing: Remove duplicate struct declaration in trace_events.h
tracing: Update create_system_filter() kernel-doc comment
tracing: A minor cleanup for create_system_filter()
kernel: trace: Mundane typo fixes in the file trace_events_filter.c
tracing: Fix various typos in comments
scripts/recordmcount.pl: Make vim and emacs indent the same
scripts/recordmcount.pl: Make indent spacing consistent
tracing: Add a verifier to check string pointers for trace events
...
Commit b40c6eabfc ("ftrace: Simplify the calculation of page number for
ftrace_page->records") simplified the calculation of the number of pages
needed for each page group without having any empty pages, but it can be
simplified even further.
Link: https://lore.kernel.org/lkml/CAHk-=wjt9b7kxQ2J=aDNKbR1QBMB3Hiqb_hYcZbKsxGRSEb+gQ@mail.gmail.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Instead of saving the size of the records field of the ftrace_page, store
the order it uses to allocate the pages, as that is what is needed to know
in order to free the pages. This simplifies the code.
Link: https://lore.kernel.org/lkml/CAHk-=whyMxheOqXAORt9a7JK9gc9eHTgCJ55Pgs4p=X3RrQubQ@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ change log written by Steven Rostedt ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Needed to merge trace/ftrace/urgent to get:
Commit 59300b36f8 ("ftrace: Check if pages were allocated before calling free_pages()")
To clean up the code that is affected by it as well.
The function addresses that are traced by ftrace are stored in pages,
and the size is held in a variable. If there's some error in creating
them, the allocate ones will be freed. In this case, it is possible that
the order of pages to be freed may end up being negative due to a size of
zero passed to get_count_order(), and then that negative number will cause
free_pages() to free a very large section. Make sure that does not happen.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYGR30BQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qnbDAP9yEhTLcDRUi3VLWnEq19Dt4Lsg86Bf
QRpbWG6Ze9EbZQEAgYAOe1fsNCNEIMXXh/4nlKVpKKH+vviS0ux9Z6uhpQQ=
=Veyq
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"Add check of order < 0 before calling free_pages()
The function addresses that are traced by ftrace are stored in pages,
and the size is held in a variable. If there's some error in creating
them, the allocate ones will be freed. In this case, it is possible
that the order of pages to be freed may end up being negative due to a
size of zero passed to get_count_order(), and then that negative
number will cause free_pages() to free a very large section.
Make sure that does not happen"
* tag 'trace-v5.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Check if pages were allocated before calling free_pages()
It is possible that on error pg->size can be zero when getting its order,
which would return a -1 value. It is dangerous to pass in an order of -1
to free_pages(). Check if order is greater than or equal to zero before
calling free_pages().
Link: https://lore.kernel.org/lkml/20210330093916.432697c7@gandalf.local.home/
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The following sequence of commands:
register_ftrace_direct(ip, addr1);
modify_ftrace_direct(ip, addr1, addr2);
unregister_ftrace_direct(ip, addr2);
will cause the kernel to warn:
[ 30.179191] WARNING: CPU: 2 PID: 1961 at kernel/trace/ftrace.c:5223 unregister_ftrace_direct+0x130/0x150
[ 30.180556] CPU: 2 PID: 1961 Comm: test_progs W O 5.12.0-rc2-00378-g86bc10a0a711-dirty #3246
[ 30.182453] RIP: 0010:unregister_ftrace_direct+0x130/0x150
When modify_ftrace_direct() changes the addr from old to new it should update
the addr stored in ftrace_direct_funcs. Otherwise the final
unregister_ftrace_direct() won't find the address and will cause the splat.
Fixes: 0567d68091 ("ftrace: Add modify_ftrace_direct()")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20210316195815.34714-1-alexei.starovoitov@gmail.com
The major update to this release is that there's a new arch config option called:
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS. Currently, only x86_64 enables it.
All the ftrace callbacks now take a struct ftrace_regs instead of a struct
pt_regs. If the architecture has HAVE_DYNAMIC_FTRACE_WITH_ARGS enabled, then
the ftrace_regs will have enough information to read the arguments of the
function being traced, as well as access to the stack pointer. This way, if
a user (like live kernel patching) only cares about the arguments, then it
can avoid using the heavier weight "regs" callback, that puts in enough
information in the struct ftrace_regs to simulate a breakpoint exception
(needed for kprobes).
New config option that audits the timestamps of the ftrace ring buffer at
most every event recorded. The "check_buffer()" calls will conflict with
mainline, because I purposely added the check without including the fix that
it caught, which is in mainline. Running a kernel built from the commit of
the added check will trigger it.
Ftrace recursion protection has been cleaned up to move the protection to
the callback itself (this saves on an extra function call for those
callbacks).
Perf now handles its own RCU protection and does not depend on ftrace to do
it for it (saving on that extra function call).
New debug option to add "recursed_functions" file to tracefs that lists all
the places that triggered the recursion protection of the function tracer.
This will show where things need to be fixed as recursion slows down the
function tracer.
The eval enum mapping updates done at boot up are now offloaded to a work
queue, as it caused a noticeable pause on slow embedded boards.
Various clean ups and last minute fixes.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCX9uq8xQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qtrwAQCHevqWMjKc1Q76bnCgwB0AbFKB6vqy
5b6g/co5+ihv8wD/eJPWlZMAt97zTVW7bdp5qj/GTiCDbAsODMZ597LsxA0=
=rZEz
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The major update to this release is that there's a new arch config
option called CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS.
Currently, only x86_64 enables it. All the ftrace callbacks now take a
struct ftrace_regs instead of a struct pt_regs. If the architecture
has HAVE_DYNAMIC_FTRACE_WITH_ARGS enabled, then the ftrace_regs will
have enough information to read the arguments of the function being
traced, as well as access to the stack pointer.
This way, if a user (like live kernel patching) only cares about the
arguments, then it can avoid using the heavier weight "regs" callback,
that puts in enough information in the struct ftrace_regs to simulate
a breakpoint exception (needed for kprobes).
A new config option that audits the timestamps of the ftrace ring
buffer at most every event recorded.
Ftrace recursion protection has been cleaned up to move the protection
to the callback itself (this saves on an extra function call for those
callbacks).
Perf now handles its own RCU protection and does not depend on ftrace
to do it for it (saving on that extra function call).
New debug option to add "recursed_functions" file to tracefs that
lists all the places that triggered the recursion protection of the
function tracer. This will show where things need to be fixed as
recursion slows down the function tracer.
The eval enum mapping updates done at boot up are now offloaded to a
work queue, as it caused a noticeable pause on slow embedded boards.
Various clean ups and last minute fixes"
* tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
tracing: Offload eval map updates to a work queue
Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"
ring-buffer: Add rb_check_bpage in __rb_allocate_pages
ring-buffer: Fix two typos in comments
tracing: Drop unneeded assignment in ring_buffer_resize()
tracing: Disable ftrace selftests when any tracer is running
seq_buf: Avoid type mismatch for seq_buf_init
ring-buffer: Fix a typo in function description
ring-buffer: Remove obsolete rb_event_is_commit()
ring-buffer: Add test to validate the time stamp deltas
ftrace/documentation: Fix RST C code blocks
tracing: Clean up after filter logic rewriting
tracing: Remove the useless value assignment in test_create_synth_event()
livepatch: Use the default ftrace_ops instead of REGS when ARGS is available
ftrace/x86: Allow for arguments to be passed in to ftrace_regs by default
ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs
MAINTAINERS: assign ./fs/tracefs to TRACING
tracing: Fix some typos in comments
ftrace: Remove unused varible 'ret'
ring-buffer: Add recording of ring buffer recursion into recursed_functions
...
On powerpc, kprobe-direct.tc triggered FTRACE_WARN_ON() in
ftrace_get_addr_new() followed by the below message:
Bad trampoline accounting at: 000000004222522f (wake_up_process+0xc/0x20) (f0000001)
The set of steps leading to this involved:
- modprobe ftrace-direct-too
- enable_probe
- modprobe ftrace-direct
- rmmod ftrace-direct <-- trigger
The problem turned out to be that we were not updating flags in the
ftrace record properly. From the above message about the trampoline
accounting being bad, it can be seen that the ftrace record still has
FTRACE_FL_TRAMP set though ftrace-direct module is going away. This
happens because we are checking if any ftrace_ops has the
FTRACE_FL_TRAMP flag set _before_ updating the filter hash.
The fix for this is to look for any _other_ ftrace_ops that also needs
FTRACE_FL_TRAMP.
Link: https://lkml.kernel.org/r/56c113aa9c3e10c19144a36d9684c7882bf09af5.1606412433.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Fixes: a124692b69 ("ftrace: Enable trampoline when rec count returns back to one")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
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>
'ret' in 2 functions are not used. and one of them is a void function.
So remove them to avoid gcc warning:
kernel/trace/ftrace.c:4166:6: warning: variable ‘ret’ set but not used
[-Wunused-but-set-variable]
kernel/trace/ftrace.c:5571:6: warning: variable ‘ret’ set but not used
[-Wunused-but-set-variable]
Link: https://lkml.kernel.org/r/1604674486-52350-1-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
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>
Now that all callbacks are recursion safe, reverse the meaning of the
RECURSION flag and rename it from RECURSION_SAFE to simply RECURSION.
Now only callbacks that request to have recursion protecting it will
have the added trampoline to do so.
Also remove the outdated comment about "PER_CPU" when determining to
use the ftrace_ops_assist_func.
Link: https://lkml.kernel.org/r/20201028115613.742454631@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.904270143@goodmis.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: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- Add support for "bool" type in synthetic events
- Add per instance tracing for bootconfig
- Support perf-style return probe ("SYMBOL%return") in kprobes and uprobes
- Allow for kprobes to be enabled earlier in boot up
- Added tracepoint helper function to allow testing if tracepoints are
enabled in headers
- Synthetic events can now have dynamic strings (variable length)
- Various fixes and cleanups
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCX4iMDRQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qrMPAP0UAfOeQcYxBAw9y8oX7oJnBBylLFTR
CICOVEhBYC/xIQD/edVPEUt77ozM/Bplwv8BiO4QxFjgZFqtpZI8mskIfAo=
=sbny
-----END PGP SIGNATURE-----
Merge tag 'trace-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Updates for tracing and bootconfig:
- Add support for "bool" type in synthetic events
- Add per instance tracing for bootconfig
- Support perf-style return probe ("SYMBOL%return") in kprobes and
uprobes
- Allow for kprobes to be enabled earlier in boot up
- Added tracepoint helper function to allow testing if tracepoints
are enabled in headers
- Synthetic events can now have dynamic strings (variable length)
- Various fixes and cleanups"
* tag 'trace-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (58 commits)
tracing: support "bool" type in synthetic trace events
selftests/ftrace: Add test case for synthetic event syntax errors
tracing: Handle synthetic event array field type checking correctly
selftests/ftrace: Change synthetic event name for inter-event-combined test
tracing: Add synthetic event error logging
tracing: Check that the synthetic event and field names are legal
tracing: Move is_good_name() from trace_probe.h to trace.h
tracing: Don't show dynamic string internals in synthetic event description
tracing: Fix some typos in comments
tracing/boot: Add ftrace.instance.*.alloc_snapshot option
tracing: Fix race in trace_open and buffer resize call
tracing: Check return value of __create_val_fields() before using its result
tracing: Fix synthetic print fmt check for use of __get_str()
tracing: Remove a pointless assignment
ftrace: ftrace_global_list is renamed to ftrace_ops_list
ftrace: Format variable declarations of ftrace_allocate_records
ftrace: Simplify the calculation of page number for ftrace_page->records
ftrace: Simplify the dyn_ftrace->flags macro
ftrace: Simplify the hash calculation
ftrace: Use fls() to get the bits for dup_hash()
...
Based on the following two reasones, we could simplify the calculation:
- If the number after roundup count is not power of 2, we would
definitely have more than 1 empty page with a higher order.
- get_count_order() just return current order, so one lower order
could meet the requirement.
The calculation could be simplified by lower one order level when pages
are not power of 2.
Link: https://lkml.kernel.org/r/20200831031104.23322-5-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
No need to add a check to subtract the number of bits if bits is zero after
fls(). Just divide the size by two before calling it. This does give the
same answer for size of 0 and 1, but that's fine.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Linus Torvalds