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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-06-28 18:49:53 +0300 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-06-28 21:11:41 +0300 |
| commit | b96285e10aad234acfa0628f7e8336990f778c03 (patch) | |
| tree | 2cb12a1addc9fde7c648a1de2fdb0c48d1c58e33 /kernel/trace/trace_osnoise.c | |
| parent | 6a2cbc58d6c9d90cd74288cc497c2b45815bc064 (diff) | |
| download | linux-b96285e10aad234acfa0628f7e8336990f778c03.tar.xz | |
tracing: Have osnoise_main() add a quiescent state for task rcu
ftracetest triggered:
INFO: rcu_tasks detected stalls on tasks:
00000000b92b832d: .. nvcsw: 1/1 holdout: 1 idle_cpu: -1/7
task:osnoise/7 state:R running task stack: 0 pid: 2133 ppid: 2 flags:0x00004000
Call Trace:
? asm_sysvec_apic_timer_interrupt+0x12/0x20
? asm_sysvec_apic_timer_interrupt+0x12/0x20
? trace_hardirqs_on+0x2b/0xe0
? asm_sysvec_apic_timer_interrupt+0x12/0x20
? trace_clock_local+0xc/0x20
? osnoise_main+0x10e/0x450
? trace_softirq_entry_callback+0x50/0x50
? kthread+0x153/0x170
? __kthread_bind_mask+0x60/0x60
? ret_from_fork+0x22/0x30
While running osnoise tracer with other tracers that rely on
synchronize_rcu_tasks(), where that just hung.
The reason is that osnoise_main() never schedules out if the interval
is less than 1, and this will cause synchronize_rcu_tasks() to never
return.
Link: https://lkml.kernel.org/r/20210628114953.6dc06a91@oasis.local.home
Fixes: bce29ac9ce0bb ("trace: Add osnoise tracer")
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_osnoise.c')
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 38aa5e208ffd..556d530af805 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1216,8 +1216,11 @@ static int osnoise_main(void *data) * differently from hwlat_detector, the osnoise tracer can run * without a pause because preemption is on. */ - if (interval < 1) + if (interval < 1) { + /* Let synchronize_rcu_tasks() make progress */ + cond_resched_tasks_rcu_qs(); continue; + } if (msleep_interruptible(interval)) break; |