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Steven Rostedt (Google) 3357c6e429 tracing: Free error logs of tracing instances 
When a tracing instance is removed, the error messages that hold errors
that occurred in the instance needs to be freed. The following reports a
memory leak:

 # cd /sys/kernel/tracing
 # mkdir instances/foo
 # echo 'hist:keys=x' > instances/foo/events/sched/sched_switch/trigger
 # cat instances/foo/error_log
 [  117.404795] hist:sched:sched_switch: error: Couldn't find field
   Command: hist:keys=x
                      ^
 # rmdir instances/foo

Then check for memory leaks:

 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88810d8ec700 (size 192):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    60 dd 68 61 81 88 ff ff 60 dd 68 61 81 88 ff ff  `.ha....`.ha....
    a0 30 8c 83 ff ff ff ff 26 00 0a 00 00 00 00 00  .0......&.......
  backtrace:
    [<00000000dae26536>] kmalloc_trace+0x2a/0xa0
    [<00000000b2938940>] tracing_log_err+0x277/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc
unreferenced object 0xffff888170c35a00 (size 32):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    0a 20 20 43 6f 6d 6d 61 6e 64 3a 20 68 69 73 74  .  Command: hist
    3a 6b 65 79 73 3d 78 0a 00 00 00 00 00 00 00 00  :keys=x.........
  backtrace:
    [<000000006a747de5>] __kmalloc+0x4d/0x160
    [<000000000039df5f>] tracing_log_err+0x29b/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc

The problem is that the error log needs to be freed when the instance is
removed.

Link: https://lore.kernel.org/lkml/76134d9f-a5ba-6a0d-37b3-28310b4a1e91@alu.unizg.hr/
Link: https://lore.kernel.org/linux-trace-kernel/20230404194504.5790b95f@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Fixes: 2f754e771b ("tracing: Have the error logs show up in the proper instances")
Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Tested-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
 		2023-04-05 09:54:37 -04:00
..
rv rv: remove redundant initialization of pointer ptr 2023-01-25 10:31:02 -05:00
Kconfig tracing updates for 6.3: 2023-02-23 10:20:49 -08:00
Makefile rv: Add Runtime Verification (RV) interface 2022-07-30 14:01:28 -04:00
blktrace.c block: remove more NULL checks after bdev_get_queue() 2023-02-21 09:23:22 -07:00
bpf_trace.c Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
bpf_trace.h
…
error_report-traces.c
…
fgraph.c arm64 fixes for 5.19-rc1: 2022-06-03 14:05:34 -07:00
fprobe.c tracing/fprobe: Fix to check whether fprobe is registered correctly 2022-11-04 08:50:07 +09:00
ftrace.c Tracing fixes for 6.3: 2023-03-19 10:46:02 -07:00
ftrace_internal.h
…
kprobe_event_gen_test.c tracing: Fix wrong return in kprobe_event_gen_test.c 2023-03-19 12:20:48 -04:00
pid_list.c tracing: Cleanup double word in comment 2022-04-26 17:58:50 -04:00
pid_list.h tracing: Create a sparse bitmask for pid filtering 2021-10-05 17:38:45 -04:00
power-traces.c
…
preemptirq_delay_test.c
…
rethook.c rethook: fix a potential memleak in rethook_alloc() 2022-11-18 10:15:34 +09:00
ring_buffer.c ring-buffer: Fix race while reader and writer are on the same page 2023-04-03 11:51:38 -04:00
ring_buffer_benchmark.c ring_buffer: Remove unused "event" parameter 2022-11-23 19:08:30 -05:00
rpm-traces.c
…
synth_event_gen_test.c tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
trace.c tracing: Free error logs of tracing instances 2023-04-05 09:54:37 -04:00
trace.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha 2023-02-25 12:49:29 -08:00
trace_benchmark.c tracing: Add numeric delta time to the trace event benchmark 2022-09-26 13:01:09 -04:00
trace_benchmark.h tracing: Add numeric delta time to the trace event benchmark 2022-09-26 13:01:09 -04:00
trace_boot.c tracing: Initialize integer variable to prevent garbage return value 2022-05-26 21:13:00 -04:00
trace_branch.c
…
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-18 09:10:00 -04:00
trace_dynevent.c tracing: Free buffers when a used dynamic event is removed 2022-11-23 19:07:12 -05:00
trace_dynevent.h tracing: Add DYNAMIC flag for dynamic events 2021-08-18 18:10:32 -04:00
trace_entries.h trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_eprobe.c kernel/trace: extract common part in process_fetch_insn 2023-02-24 10:04:13 +09:00
trace_event_perf.c tracing/perf: Use strndup_user instead of kzalloc/strncpy_from_user 2022-11-23 19:08:31 -05:00
trace_events.c tracing updates for 6.3: 2023-02-23 10:20:49 -08:00
trace_events_filter.c tracing: Add a way to filter function addresses to function names 2023-01-25 10:31:11 -05:00
trace_events_filter_test.h
…
trace_events_hist.c tracing: Check field value in hist_field_name() 2023-03-09 22:17:06 -05:00
trace_events_inject.c tracing: Support __rel_loc relative dynamic data location attribute 2021-12-06 15:37:21 -05:00
trace_events_synth.c tracing/synthetic: Fix races on freeing last_cmd 2023-04-03 11:51:12 -04:00
trace_events_trigger.c tracing: Do not synchronize freeing of trigger filter on boot up 2022-12-14 08:50:56 -05:00
trace_events_user.c Tracing updates for 6.2: 2022-12-15 18:01:16 -08:00
trace_export.c tracing: Fix TASK_COMM_LEN in trace event format file 2023-02-12 10:23:39 -05:00
trace_functions.c ftrace: disable preemption when recursion locked 2021-10-27 11:21:49 -04:00
trace_functions_graph.c tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
trace_hwlat.c tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr 2023-03-19 13:23:22 -04:00
trace_irqsoff.c
…
trace_kdb.c kdb: Rename members of struct kdbtab_t 2021-07-27 17:05:06 +01:00
trace_kprobe.c kernel/trace: extract common part in process_fetch_insn 2023-02-24 10:04:13 +09:00
trace_kprobe_selftest.c
…
trace_kprobe_selftest.h
…
trace_mmiotrace.c
…
trace_nop.c
…
trace_osnoise.c tracing/osnoise: Fix notify new tracing_max_latency 2023-04-03 11:52:46 -04:00
trace_output.c tracing: Make sure trace_printk() can output as soon as it can be used 2023-01-24 11:27:29 -05:00
trace_output.h
…
trace_preemptirq.c cpuidle: tracing, preempt: Squash _rcuidle tracing 2023-01-31 15:01:46 +01:00
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_probe.c kernel/trace: Introduce trace_probe_print_args and use it in *probes 2023-02-24 09:44:15 +09:00
trace_probe.h kernel/trace: Introduce trace_probe_print_args and use it in *probes 2023-02-24 09:44:15 +09:00
trace_probe_kernel.h kernel/trace: Provide default impelentations defined in trace_probe_tmpl.h 2023-02-24 09:44:27 +09:00
trace_probe_tmpl.h kernel/trace: extract common part in process_fetch_insn 2023-02-24 10:04:13 +09:00
trace_recursion_record.c tracing: Use trace_create_file() to simplify creation of tracefs entries 2022-05-26 21:12:52 -04:00
trace_sched_switch.c sched/tracing: Append prev_state to tp args instead 2022-05-12 00:37:11 +02:00
trace_sched_wakeup.c sched/tracing: Append prev_state to tp args instead 2022-05-12 00:37:11 +02:00
trace_selftest.c x86/ftrace: Make it call depth tracking aware 2022-10-17 16:41:19 +02:00
trace_selftest_dynamic.c
…
trace_seq.c tracing: Acquire buffer from temparary trace sequence 2023-02-07 12:42:54 -05:00
trace_stack.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.h
…
trace_synth.h tracing: Allow synthetic events to pass around stacktraces 2023-01-25 10:31:24 -05:00
trace_syscalls.c tracing: Remove unused __bad_type_size() method 2022-11-17 20:21:06 -05:00
trace_uprobe.c kernel/trace: extract common part in process_fetch_insn 2023-02-24 10:04:13 +09:00
tracing_map.c tracing: Remove unused variable 'dups' 2022-10-03 12:20:31 -04:00
tracing_map.h
…