01 Dec, 2020
1 commit
-
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
Signed-off-by: Steven Rostedt (VMware)
16 Oct, 2020
1 commit
-
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()
...
09 Oct, 2020
4 commits
-
I hate when unrelated variables are declared on the same line.
Split them.Signed-off-by: Steven Rostedt (VMware)
-
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
Signed-off-by: Steven Rostedt (VMware) -
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)
-
The effect here is to get the number of bits, lets use fls() to do
this job.Link: https://lkml.kernel.org/r/20200831031104.23322-3-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang
Signed-off-by: Steven Rostedt (VMware)
03 Oct, 2020
1 commit
-
s/coorditate/coordinate/
s/emty/empty/
s/preeptive/preemptive/
s/succes/success/
s/carefule/careful/Link: https://lkml.kernel.org/r/20201002143126.2890-1-hqjagain@gmail.com
Signed-off-by: Qiujun Huang
Signed-off-by: Steven Rostedt (VMware)
30 Sep, 2020
1 commit
-
The first thing that the ftrace function callback helper functions should do
is to check for recursion. Peter Zijlstra found that when
"rcu_is_watching()" had its notrace removed, it caused perf function tracing
to crash. This is because the call of rcu_is_watching() is tested before
function recursion is checked and and if it is traced, it will cause an
infinite recursion loop.rcu_is_watching() should still stay notrace, but to prevent this should
never had crashed in the first place. The recursion prevention must be the
first thing done in callback functions.Link: https://lore.kernel.org/r/20200929112541.GM2628@hirez.programming.kicks-ass.net
Cc: stable@vger.kernel.org
Cc: Paul McKenney
Fixes: c68c0fa293417 ("ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too")
Acked-by: Peter Zijlstra (Intel)
Reported-by: Peter Zijlstra (Intel)
Signed-off-by: Steven Rostedt (VMware)
22 Sep, 2020
1 commit
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Drop repeated words in kernel/trace/.
{and, the, not}Link: https://lkml.kernel.org/r/20200807033259.13778-1-rdunlap@infradead.org
Cc: Ingo Molnar
Signed-off-by: Randy Dunlap
Signed-off-by: Steven Rostedt (VMware)
19 Sep, 2020
3 commits
-
Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of ftrace_enable_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:kernel/trace/ftrace.c:7544:43: warning: incorrect type in argument 3 (different address spaces)
kernel/trace/ftrace.c:7544:43: expected void *
kernel/trace/ftrace.c:7544:43: got void [noderef] __user *bufferLink: https://lkml.kernel.org/r/20200907093207.13540-1-tklauser@distanz.ch
Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Cc: Andrew Morton
Cc: Ingo Molnar
Cc: Christoph Hellwig
Cc: Al Viro
Signed-off-by: Tobias Klauser
Signed-off-by: Steven Rostedt (VMware) -
Add synchronize_rcu() after list_del_rcu() in
ftrace_remove_trampoline_from_kallsyms() to protect readers of
ftrace_ops_trampoline_list (in ftrace_get_trampoline_kallsym)
which is used when kallsyms is read.Link: https://lkml.kernel.org/r/20200901091617.31837-1-adrian.hunter@intel.com
Fixes: fc0ea795f53c8d ("ftrace: Add symbols for ftrace trampolines")
Signed-off-by: Adrian Hunter
Signed-off-by: Steven Rostedt (VMware) -
Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
missed to remove ops from new ftrace_ops_trampoline_list in
ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
lead to BUG if such ops come from a module which may be removed.Moreover, the trampoline itself is not freed in this case.
Fix it by calling ftrace_trampoline_free() during the rollback.
Link: https://lkml.kernel.org/r/20200831122631.28057-1-mbenes@suse.cz
Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict")
Signed-off-by: Miroslav Benes
Signed-off-by: Steven Rostedt (VMware)
08 Aug, 2020
1 commit
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Pull tracing updates from Steven Rostedt:
- The biggest news in that the tracing ring buffer can now time events
that interrupted other ring buffer events.Before this change, if an interrupt came in while recording another
event, and that interrupt also had an event, those events would all
have the same time stamp as the event it interrupted.Now, with the new design, those events will have a unique time stamp
and rightfully display the time for those events that were recorded
while interrupting another event.- Bootconfig how has an "override" operator that lets the users have a
default config, but then add options to override the default.- A fix was made to properly filter function graph tracing to the
ftrace PIDs. This came in at the end of the -rc cycle, and needs to
be backported.- Several clean ups, performance updates, and minor fixes as well.
* tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (39 commits)
tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers
kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE
tracing: Use trace_sched_process_free() instead of exit() for pid tracing
bootconfig: Fix to find the initargs correctly
Documentation: bootconfig: Add bootconfig override operator
tools/bootconfig: Add testcases for value override operator
lib/bootconfig: Add override operator support
kprobes: Remove show_registers() function prototype
tracing/uprobe: Remove dead code in trace_uprobe_register()
kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler
ftrace: Fix ftrace_trace_task return value
tracepoint: Use __used attribute definitions from compiler_attributes.h
tracepoint: Mark __tracepoint_string's __used
trace : Have tracing buffer info use kvzalloc instead of kzalloc
tracing: Remove outdated comment in stack handling
ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines
ftrace: Setup correct FTRACE_FL_REGS flags for module
tracing/hwlat: Honor the tracing_cpumask
tracing/hwlat: Drop the duplicate assignment in start_kthread()
tracing: Save one trace_event->type by using __TRACE_LAST_TYPE
...
05 Aug, 2020
1 commit
-
On exit, if a process is preempted after the trace_sched_process_exit()
tracepoint but before the process is done exiting, then when it gets
scheduled in, the function tracers will not filter it properly against the
function tracing pid filters.That is because the function tracing pid filters hooks to the
sched_process_exit() tracepoint to remove the exiting task's pid from the
filter list. Because the filtering happens at the sched_switch tracepoint,
when the exiting task schedules back in to finish up the exit, it will no
longer be in the function pid filtering tables.This was noticeable in the notrace self tests on a preemptable kernel, as
the tests would fail as it exits and preempted after being taken off the
notrace filter table and on scheduling back in it would not be in the
notrace list, and then the ending of the exit function would trace. The test
detected this and would fail.Cc: stable@vger.kernel.org
Cc: Namhyung Kim
Fixes: 1e10486ffee0a ("ftrace: Add 'function-fork' trace option")
Fixes: c37775d57830a ("tracing: Add infrastructure to allow set_event_pid to follow children"
Signed-off-by: Steven Rostedt (VMware)
04 Aug, 2020
1 commit
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I was attempting to use pid filtering with function_graph, but it wasn't
allowing anything to make it through. Turns out ftrace_trace_task
returns false if ftrace_ignore_pid is not-empty, which isn't correct
anymore. We're now setting it to FTRACE_PID_IGNORE if we need to ignore
that pid, otherwise it's set to the pid (which is weird considering the
name) or to FTRACE_PID_TRACE. Fix the check to check for !=
FTRACE_PID_IGNORE. With this we can now use function_graph with pid
filtering.Link: https://lkml.kernel.org/r/20200725005048.1790-1-josef@toxicpanda.com
Fixes: 717e3f5ebc82 ("ftrace: Make function trace pid filtering a bit more exact")
Signed-off-by: Josef Bacik
Signed-off-by: Steven Rostedt (VMware)
31 Jul, 2020
2 commits
-
When inserting a module, we find all ftrace_ops referencing it on the
ftrace_ops_list. But FTRACE_OPS_FL_DIRECT and FTRACE_OPS_FL_IPMODIFY
flags are special, and should not be set automatically. So warn and
skip ftrace_ops that have these two flags set and adding new code.
Also check if only one ftrace_ops references the module, in which case
we can use a trampoline as an optimization.Link: https://lkml.kernel.org/r/20200728180554.65203-2-zhouchengming@bytedance.com
Signed-off-by: Chengming Zhou
Signed-off-by: Muchun Song
Signed-off-by: Steven Rostedt (VMware) -
When module loaded and enabled, we will use __ftrace_replace_code
for module if any ftrace_ops referenced it found. But we will get
wrong ftrace_addr for module rec in ftrace_get_addr_new, because
rec->flags has not been setup correctly. It can cause the callback
function of a ftrace_ops has FTRACE_OPS_FL_SAVE_REGS to be called
with pt_regs set to NULL.
So setup correct FTRACE_FL_REGS flags for rec when we call
referenced_filters to find ftrace_ops references it.Link: https://lkml.kernel.org/r/20200728180554.65203-1-zhouchengming@bytedance.com
Cc: stable@vger.kernel.org
Fixes: 8c4f3c3fa9681 ("ftrace: Check module functions being traced on reload")
Signed-off-by: Chengming Zhou
Signed-off-by: Muchun Song
Signed-off-by: Steven Rostedt (VMware)
02 Jul, 2020
1 commit
29 Jun, 2020
1 commit
-
If a direct hook is attached to a function that ftrace also has a function
attached to it, then it is required that the ftrace_ops_list_func() is used
to iterate over the registered ftrace callbacks. This will also include the
direct ftrace_ops helper, that tells ftrace_regs_caller where to return to
(the direct callback and not the function that called it).As this direct helper is only to handle the case of ftrace callbacks
attached to the same function as the direct callback, the ftrace callback
allocated trampolines (used to only call them), should never be used to
return back to a direct callback.Only copy the portion of the ftrace_regs_caller that will return back to
what called it, and not the portion that returns back to the direct caller.The direct ftrace_ops must then pick the ftrace_regs_caller builtin function
as its own trampoline to ensure that it will never have one allocated for
it (which would not include the handling of direct callbacks).Link: http://lkml.kernel.org/r/20200422162750.495903799@goodmis.org
Cc: Peter Zijlstra
Signed-off-by: Steven Rostedt (VMware)
18 Jun, 2020
1 commit
-
During build compiler reports some 'false positive' warnings about
variables {'seq_ops', 'filtered_pids', 'other_pids'} may be used
uninitialized. This patch silences these warnings.
Also delete some useless spacesLink: https://lkml.kernel.org/r/20200529141214.37648-1-pilgrimtao@gmail.com
Signed-off-by: Kaitao Cheng
Signed-off-by: Steven Rostedt (VMware)
15 Jun, 2020
3 commits
-
Add perf text poke events for ftrace trampolines when created and when
freed.There can be 3 text_poke events for ftrace trampolines:
1. NULL -> trampoline
By ftrace_update_trampoline() when !ops->trampoline
Trampoline created2. [e.g. on x86] CALL rel32 -> CALL rel32
By arch_ftrace_update_trampoline() when ops->trampoline and
ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP
[e.g. on x86] via text_poke_bp() which generates text poke events
Trampoline-called function target updated3. trampoline -> NULL
By ftrace_trampoline_free() when ops->trampoline and
ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP
Trampoline freedSigned-off-by: Adrian Hunter
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Peter Zijlstra (Intel)
Link: https://lkml.kernel.org/r/20200512121922.8997-9-adrian.hunter@intel.com -
Symbols are needed for tools to describe instruction addresses. Pages
allocated for ftrace's purposes need symbols to be created for them.
Add such symbols to be visible via perf ksymbol events.Signed-off-by: Adrian Hunter
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Peter Zijlstra (Intel)
Link: https://lkml.kernel.org/r/20200512121922.8997-8-adrian.hunter@intel.com -
Symbols are needed for tools to describe instruction addresses. Pages
allocated for ftrace's purposes need symbols to be created for them.
Add such symbols to be visible via /proc/kallsyms.Example on x86 with CONFIG_DYNAMIC_FTRACE=y
# echo function > /sys/kernel/debug/tracing/current_tracer
# cat /proc/kallsyms | grep '\[__builtin__ftrace\]'
ffffffffc0238000 t ftrace_trampoline [__builtin__ftrace]Note: This patch adds "__builtin__ftrace" as a module name in /proc/kallsyms for
symbols for pages allocated for ftrace's purposes, even though "__builtin__ftrace"
is not a module.Signed-off-by: Adrian Hunter
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Peter Zijlstra (Intel)
Link: https://lkml.kernel.org/r/20200512121922.8997-7-adrian.hunter@intel.com
10 Jun, 2020
2 commits
-
Pull tracing updates from Steven Rostedt:
"No new features this release. Mostly clean ups, restructuring and
documentation.- Have ftrace_bug() show ftrace errors before the WARN, as the WARN
will reboot the box before the error messages are printed if
panic_on_warn is set.- Have traceoff_on_warn disable tracing sooner (before prints)
- Write a message to the trace buffer that its being disabled when
disable_trace_on_warning() is set.- Separate out synthetic events from histogram code to let it be used
by other parts of the kernel.- More documentation on histogram design.
- Other small fixes and clean ups"
* tag 'trace-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option
tracing/doc: Fix ascii-art in histogram-design.rst
tracing: Add a trace print when traceoff_on_warning is triggered
ftrace,bug: Improve traceoff_on_warn
selftests/ftrace: Distinguish between hist and synthetic event checks
tracing: Move synthetic events to a separate file
tracing: Fix events.rst section numbering
tracing/doc: Fix typos in histogram-design.rst
tracing: Add hist_debug trace event files for histogram debugging
tracing: Add histogram-design document
tracing: Check state.disabled in synth event trace functions
tracing/probe: reverse arguments to list_add
tools/bootconfig: Add a summary of test cases and return error
ftrace: show debugging information when panic_on_warn set -
Patch series "Add log level to show_stack()", v3.
Add log level argument to show_stack().
Done in three stages:
1. Introducing show_stack_loglvl() for every architecture
2. Migrating old users with an explicit log level
3. Renaming show_stack_loglvl() into show_stack()Justification:
- It's a design mistake to move a business-logic decision into platform
realization detail.- I have currently two patches sets that would benefit from this work:
Removing console_loglevel jumps in sysrq driver [1] Hung task warning
before panic [2] - suggested by Tetsuo (but he probably didn't realise
what it would involve).- While doing (1), (2) the backtraces were adjusted to headers and other
messages for each situation - so there won't be a situation when the
backtrace is printed, but the headers are missing because they have
lesser log level (or the reverse).- As the result in (2) plays with console_loglevel for kdb are removed.
The least important for upstream, but maybe still worth to note that every
company I've worked in so far had an off-list patch to print backtrace
with the needed log level (but only for the architecture they cared
about). If you have other ideas how you will benefit from show_stack()
with a log level - please, reply to this cover letter.See also discussion on v1:
https://lore.kernel.org/linux-riscv/20191106083538.z5nlpuf64cigxigh@pathway.suse.cz/This patch (of 50):
print_ip_sym() needs to have a log level parameter to comply with other
parts being printed. Otherwise, half of the expected backtrace would be
printed and other may be missing with some logging level.The following callee(s) are using now the adjusted log level:
- microblaze/unwind: the same level as headers & userspace unwind.
Note that pr_debug()'s there are for debugging the unwinder itself.
- nds32/traps: symbol addresses are printed with the same log level
as backtrace headers.
- lockdep: ip for locking issues is printed with the same log level
as other part of the warning.
- sched: ip where preemption was disabled is printed as error like
the rest part of the message.
- ftrace: bug reports are now consistent in the log level being used.Signed-off-by: Dmitry Safonov
Signed-off-by: Andrew Morton
Acked-by: Steven Rostedt (VMware)
Cc: Albert Ou
Cc: Ben Segall
Cc: Dietmar Eggemann
Cc: Greentime Hu
Cc: Greg Kroah-Hartman
Cc: Ingo Molnar
Cc: James Hogan
Cc: Juri Lelli
Cc: Mel Gorman
Cc: Michal Simek
Cc: Palmer Dabbelt
Cc: Paul Burton
Cc: Paul Walmsley
Cc: Peter Zijlstra
Cc: Ralf Baechle
Cc: Thomas Gleixner
Cc: Vincent Chen
Cc: Vincent Guittot
Cc: Will Deacon
Cc: Dmitry Safonov
Cc: Dmitry Safonov
Cc: Jiri Slaby
Cc: Petr Mladek
Cc: Sergey Senozhatsky
Cc: Ivan Kokshaysky
Cc: Matt Turner
Cc: Richard Henderson
Cc: Vineet Gupta
Cc: Russell King
Cc: Catalin Marinas
Cc: Aurelien Jacquiot
Cc: Mark Salter
Cc: Guo Ren
Cc: Yoshinori Sato
Cc: Brian Cain
Cc: Fenghua Yu
Cc: Tony Luck
Cc: Geert Uytterhoeven
Cc: Ley Foon Tan
Cc: Jonas Bonn
Cc: Stafford Horne
Cc: Stefan Kristiansson
Cc: Helge Deller
Cc: "James E.J. Bottomley"
Cc: Benjamin Herrenschmidt
Cc: Michael Ellerman
Cc: Paul Mackerras
Cc: Christian Borntraeger
Cc: Heiko Carstens
Cc: Vasily Gorbik
Cc: Rich Felker
Cc: "David S. Miller"
Cc: Anton Ivanov
Cc: Jeff Dike
Cc: Richard Weinberger
Cc: Guan Xuetao
Cc: Borislav Petkov
Cc: "H. Peter Anvin"
Cc: Chris Zankel
Cc: Max Filippov
Cc: Len Brown
Cc: Pavel Machek
Cc: "Rafael J. Wysocki"
Cc: "Rafael J. Wysocki"
Cc: Daniel Thompson
Cc: Douglas Anderson
Cc: Jason Wessel
Link: http://lkml.kernel.org/r/20200418201944.482088-2-dima@arista.com
Signed-off-by: Linus Torvalds
20 May, 2020
1 commit
-
When an anomaly is detected in the function call modification
code, ftrace_bug() is called to disable function tracing as well
as give some warn and information that may help debug the problem.But currently, we call FTRACE_WARN_ON_ONCE() first in ftrace_bug(),
so when panic_on_warn is set, we can't see the debugging information
here. Call FTRACE_WARN_ON_ONCE() at the end of ftrace_bug() to ensure
that the debugging information is displayed first.after this patch, the dmesg looks like:
------------[ ftrace bug ]------------
ftrace failed to modify
[] bcm2835_handle_irq+0x4/0x58
actual: 1f:20:03:d5
Setting ftrace call site to call ftrace function
ftrace record flags: 80000001
(1)
expected tramp: ffff80001009d6f0
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1635 at kernel/trace/ftrace.c:2078 ftrace_bug+0x204/0x238
Kernel panic - not syncing: panic_on_warn set ...
CPU: 2 PID: 1635 Comm: sh Not tainted 5.7.0-rc5-00033-gb922183867f5 #14
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x1b0
show_stack+0x20/0x30
dump_stack+0xc0/0x10c
panic+0x16c/0x368
__warn+0x120/0x160
report_bug+0xc8/0x160
bug_handler+0x28/0x98
brk_handler+0x70/0xd0
do_debug_exception+0xcc/0x1ac
el1_sync_handler+0xe4/0x120
el1_sync+0x7c/0x100
ftrace_bug+0x204/0x238Link: https://lkml.kernel.org/r/20200515100828.7091-1-cj.chengjian@huawei.com
Signed-off-by: Cheng Jian
Signed-off-by: Steven Rostedt (VMware)
19 May, 2020
1 commit
-
Get the noinstr section and annotation markers to base the RCU parts on.
28 Apr, 2020
1 commit
-
This commit replaces the schedule_on_each_cpu(ftrace_sync) instances
with synchronize_rcu_tasks_rude().Suggested-by: Steven Rostedt
Cc: Ingo Molnar
[ paulmck: Make Kconfig adjustments noted by kbuild test robot. ]
Signed-off-by: Paul E. McKenney
23 Apr, 2020
1 commit
-
kmemleak reported the following:
unreferenced object 0xffff90d47127a920 (size 32):
comm "modprobe", pid 1766, jiffies 4294792031 (age 162.568s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 22 01 00 00 00 00 ad de ........".......
00 78 12 a7 ff ff ff ff 00 00 b6 c0 ff ff ff ff .x..............
backtrace:
[] register_ftrace_direct+0xcb/0x3a0
[] do_one_initcall+0x72/0x340
[] do_init_module+0x5a/0x220
[] load_module+0x2235/0x2550
[] __do_sys_finit_module+0xc0/0x120
[] do_syscall_64+0x60/0x230
[] entry_SYSCALL_64_after_hwframe+0x49/0xb3The entry used to save the direct descriptor needs to be freed
when unregistering.Signed-off-by: Steven Rostedt (VMware)
06 Apr, 2020
1 commit
-
Pull tracing updates from Steven Rostedt:
"New tracing features:- The ring buffer is no longer disabled when reading the trace file.
The trace_pipe file was made to be used for live tracing and
reading as it acted like the normal producer/consumer. As the trace
file would not consume the data, the easy way of handling it was to
just disable writes to the ring buffer.This came to a surprise to the BPF folks who complained about lost
events due to reading. This is no longer an issue. If someone wants
to keep the old disabling there's a new option "pause-on-trace"
that can be set.- New set_ftrace_notrace_pid file. PIDs in this file will not be
traced by the function tracer.Similar to set_ftrace_pid, which makes the function tracer only
trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
does the reverse.- New set_event_notrace_pid file. PIDs in this file will cause events
not to be traced if triggered by a task with a matching PID.Similar to the set_event_pid file but will not be traced. Note,
sched_waking and sched_switch events may still be traced if one of
the tasks referenced by those events contains a PID that is allowed
to be traced.Tracing related features:
- New bootconfig option, that is attached to the initrd file.
If bootconfig is on the command line, then the initrd file is
searched looking for a bootconfig appended at the end.- New GPU tracepoint infrastructure to help the gfx drivers to get
off debugfs (acked by Greg Kroah-Hartman)And other minor updates and fixes"
* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
tracing: Do not allocate buffer in trace_find_next_entry() in atomic
tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
selftests/ftrace: Add test to test new set_event_notrace_pid file
selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
tracing: Create set_event_notrace_pid to not trace tasks
ftrace: Create set_ftrace_notrace_pid to not trace tasks
ftrace: Make function trace pid filtering a bit more exact
ftrace/kprobe: Show the maxactive number on kprobe_events
tracing: Have the document reflect that the trace file keeps tracing enabled
ring-buffer/tracing: Have iterator acknowledge dropped events
tracing: Do not disable tracing when reading the trace file
ring-buffer: Do not disable recording when there is an iterator
ring-buffer: Make resize disable per cpu buffer instead of total buffer
ring-buffer: Optimize rb_iter_head_event()
ring-buffer: Do not die if rb_iter_peek() fails more than thrice
ring-buffer: Have rb_iter_head_event() handle concurrent writer
ring-buffer: Add page_stamp to iterator for synchronization
ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
tracing: Save off entry when peeking at next entry
...
28 Mar, 2020
3 commits
-
There's currently a way to select a task that should only have its events
traced, but there's no way to select a task not to have itsevents traced.
Add a set_event_notrace_pid file that acts the same as set_event_pid (and is
also affected by event-fork), but the task pids in this file will not be
traced even if they are listed in the set_event_pid file. This makes it easy
for tools like trace-cmd to "hide" itself from beint traced by events when
it is recording other tasks.Signed-off-by: Steven Rostedt (VMware)
-
There's currently a way to select a task that should only be traced by
functions, but there's no way to select a task not to be traced by the
function tracer. Add a set_ftrace_notrace_pid file that acts the same as
set_ftrace_pid (and is also affected by function-fork), but the task pids in
this file will not be traced even if they are listed in the set_ftrace_pid
file. This makes it easy for tools like trace-cmd to "hide" itself from the
function tracer when it is recording other tasks.Signed-off-by: Steven Rostedt (VMware)
-
The set_ftrace_pid file is used to filter function tracing to only trace
tasks that are listed in that file. Instead of testing the pids listed in
that file (it's a bitmask) at each function trace event, the logic is done
via a sched_switch hook. A flag is set when the next task to run is in the
list of pids in the set_ftrace_pid file. But the sched_switch hook is not at
the exact location of when the task switches, and the flag gets set before
the task to be traced actually runs. This leaves a residue of traced
functions that do not belong to the pid that should be filtered on.By changing the logic slightly, where instead of having a boolean flag to
test, record the pid that should be traced, with special values for not to
trace and always trace. Then at each function call, a check will be made to
see if the function should be ignored, or if the current pid matches the
function that should be traced, and only trace if it matches (or if it has
the special value to always trace).Signed-off-by: Steven Rostedt (VMware)
11 Mar, 2020
1 commit
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It appears that ip ranges can overlap so. In that case lookup_rec()
returns whatever results it got last even if it found nothing in last
searched page.This breaks an obscure livepatch late module patching usecase:
- load livepatch
- load the patched module
- unload livepatch
- try to load livepatch againTo fix this return from lookup_rec() as soon as it found the record
containing searched-for ip. This used to be this way prior lookup_rec()
introduction.Link: http://lkml.kernel.org/r/20200306174317.21699-1-asavkov@redhat.com
Cc: stable@vger.kernel.org
Fixes: 7e16f581a817 ("ftrace: Separate out functionality from ftrace_location_range()")
Signed-off-by: Artem Savkov
Signed-off-by: Steven Rostedt (VMware)
06 Feb, 2020
3 commits
-
As function_graph tracer can run when RCU is not "watching", it can not be
protected by synchronize_rcu() it requires running a task on each CPU before
it can be freed. Calling schedule_on_each_cpu(ftrace_sync) needs to be used.Link: https://lore.kernel.org/r/20200205131110.GT2935@paulmck-ThinkPad-P72
Cc: stable@vger.kernel.org
Fixes: b9b0c831bed26 ("ftrace: Convert graph filter to use hash tables")
Reported-by: "Paul E. McKenney"
Reviewed-by: Joel Fernandes (Google)
Signed-off-by: Steven Rostedt (VMware) -
Fix following instances of sparse error
kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5870:25: error: incompatible types in comparisonUse rcu_dereference_protected to dereference the newly annotated pointer.
Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com
Signed-off-by: Amol Grover
Signed-off-by: Steven Rostedt (VMware) -
Fix following instances of sparse error
kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5866:25: error: incompatible types in comparisonUse rcu_dereference_protected to access the __rcu annotated pointer.
Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com
Reviewed-by: Joel Fernandes (Google)
Signed-off-by: Amol Grover
Signed-off-by: Steven Rostedt (VMware)
30 Jan, 2020
1 commit
-
if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.Without patch:
# dd bs=4 skip=1 if=/sys/kernel/tracing/set_ftrace_pid
dd: /sys/kernel/tracing/set_ftrace_pid: cannot skip to specified offset
id
no pid
2+1 records in
2+1 records out
10 bytes copied, 0.000213285 s, 46.9 kB/sNotice the "id" followed by "no pid".
With the patch:
# dd bs=4 skip=1 if=/sys/kernel/tracing/set_ftrace_pid
dd: /sys/kernel/tracing/set_ftrace_pid: cannot skip to specified offset
id
0+1 records in
0+1 records out
3 bytes copied, 0.000202112 s, 14.8 kB/sNotice that it only prints "id" and not the "no pid" afterward.
Link: http://lkml.kernel.org/r/4f87c6ad-f114-30bb-8506-c32274ce2992@virtuozzo.com
https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin
Signed-off-by: Steven Rostedt (VMware)
25 Jan, 2020
1 commit
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As warnings can trigger panics, especially when "panic_on_warn" is set,
memory failure warnings can cause panics and fail fuzz testers that are
stressing memory.Create a MEM_FAIL() macro to use instead of WARN() in the tracing code
(perhaps this should be a kernel wide macro?), and use that for memory
failure issues. This should stop failing fuzz tests due to warnings.Link: https://lore.kernel.org/r/CACT4Y+ZP-7np20GVRu3p+eZys9GPtbu+JpfV+HtsufAzvTgJrg@mail.gmail.com
Suggested-by: Dmitry Vyukov
Signed-off-by: Steven Rostedt (VMware)
22 Jan, 2020
1 commit
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This macro isn't used from commit cb7be3b2fc2c ("ftrace: remove
daemon"). So no needs to keep it.Link: http://lkml.kernel.org/r/1579586063-44984-1-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi
Signed-off-by: Steven Rostedt (VMware)
