diff options
| author | Valentin Schneider <valentin.schneider@arm.com> | 2022-01-20 19:25:19 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-01 18:18:39 +0300 |
| commit | fa2c3254d7cfff5f7a916ab928a562d1165f17bb (patch) | |
| tree | 678cc10a62564212f526fc4a65ea345fde95794e /kernel/trace/trace_sched_switch.c | |
| parent | 49bef33e4b87b743495627a529029156c6e09530 (diff) | |
| download | linux-fa2c3254d7cfff5f7a916ab928a562d1165f17bb.tar.xz | |
sched/tracing: Don't re-read p->state when emitting sched_switch event
As of commit
c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu")
the following sequence becomes possible:
p->__state = TASK_INTERRUPTIBLE;
__schedule()
deactivate_task(p);
ttwu()
READ !p->on_rq
p->__state=TASK_WAKING
trace_sched_switch()
__trace_sched_switch_state()
task_state_index()
return 0;
TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in
the trace event.
Prevent this by pushing the value read from __schedule() down the trace
event.
Reported-by: Abhijeet Dharmapurikar <adharmap@quicinc.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com
Diffstat (limited to 'kernel/trace/trace_sched_switch.c')
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index e304196d7c28..993b0ed10d8c 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -22,6 +22,7 @@ static DEFINE_MUTEX(sched_register_mutex); static void probe_sched_switch(void *ignore, bool preempt, + unsigned int prev_state, struct task_struct *prev, struct task_struct *next) { int flags; |