linux/kernel/trace/ftrace.c, branch v5.8

ftrace: Fix maybe-uninitialized compiler warning

2020-06-17T21:13:18Z

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 spaces Link: https://lkml.kernel.org/r/20200529141214.37648-1-pilgrimtao@gmail.com Signed-off-by: Kaitao Cheng Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-06-09T17:06:18Z

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

kallsyms/printk: add loglvl to print_ip_sym()

2020-06-09T16:39:10Z

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 <0x7f454c46@gmail.com> 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

ftrace: show debugging information when panic_on_warn set

2020-05-20T01:08:01Z

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+0x204/0x238 Link: https://lkml.kernel.org/r/20200515100828.7091-1-cj.chengjian@huawei.com Signed-off-by: Cheng Jian Signed-off-by: Steven Rostedt (VMware)

Merge tag 'noinstr-lds-2020-05-19' into core/rcu

2020-05-19T13:50:34Z

Get the noinstr section and annotation markers to base the RCU parts on.

ftrace: Use synchronize_rcu_tasks_rude() instead of ftrace_sync()

2020-04-27T18:03:53Z

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

ftrace: Fix memory leak caused by not freeing entry in unregister_ftrace_direct()

2020-04-23T02:04:27Z

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: [<00000000bb79e72e>] register_ftrace_direct+0xcb/0x3a0 [<00000000295e4f79>] do_one_initcall+0x72/0x340 [<00000000873ead18>] do_init_module+0x5a/0x220 [<00000000974d9de5>] load_module+0x2235/0x2550 [<0000000059c3d6ce>] __do_sys_finit_module+0xc0/0x120 [<000000005a8611b4>] do_syscall_64+0x60/0x230 [<00000000a0cdc49e>] entry_SYSCALL_64_after_hwframe+0x49/0xb3 The entry used to save the direct descriptor needs to be freed when unregistering. Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-04-05T17:36:18Z

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 ...

tracing: Create set_event_notrace_pid to not trace tasks

2020-03-27T20:39:02Z

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)

ftrace: Create set_ftrace_notrace_pid to not trace tasks

2020-03-27T20:39:02Z

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)