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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2019-08-17 16:12:08 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-01-30 15:46:10 +0100 |
| commit | 64ae572bc7d0060429e40e1c8d803ce5eb31a0d6 (patch) | |
| tree | 411822258e8207664a919baee588d43f081fe4ce /kernel/trace/trace_sched_switch.c | |
| parent | tracing/boot: Move external function declarations to kernel/trace/trace.h (diff) | |
| download | linux-64ae572bc7d0060429e40e1c8d803ce5eb31a0d6.tar.xz linux-64ae572bc7d0060429e40e1c8d803ce5eb31a0d6.zip | |
tracing: Fix sched switch start/stop refcount racy updates
Reading the sched_cmdline_ref and sched_tgid_ref initial state within
tracing_start_sched_switch without holding the sched_register_mutex is
racy against concurrent updates, which can lead to tracepoint probes
being registered more than once (and thus trigger warnings within
tracepoint.c).
[ May be the fix for this bug ]
Link: https://lore.kernel.org/r/000000000000ab6f84056c786b93@google.com
Link: http://lkml.kernel.org/r/20190817141208.15226-1-mathieu.desnoyers@efficios.com
Cc: stable@vger.kernel.org
CC: Steven Rostedt (VMware) <rostedt@goodmis.org>
CC: Joel Fernandes (Google) <joel@joelfernandes.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul E. McKenney <paulmck@linux.ibm.com>
Reported-by: syzbot+774fddf07b7ab29a1e55@syzkaller.appspotmail.com
Fixes: d914ba37d7145 ("tracing: Add support for recording tgid of tasks")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_sched_switch.c')
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index e288168661e1..e304196d7c28 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -89,8 +89,10 @@ static void tracing_sched_unregister(void) static void tracing_start_sched_switch(int ops) { - bool sched_register = (!sched_cmdline_ref && !sched_tgid_ref); + bool sched_register; + mutex_lock(&sched_register_mutex); + sched_register = (!sched_cmdline_ref && !sched_tgid_ref); switch (ops) { case RECORD_CMDLINE: |