* [PATCH] signal condition variable at end of stop_tracers
@ 2014-09-08 7:38 Robert Schiele
2014-09-08 14:16 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Robert Schiele @ 2014-09-08 7:38 UTC (permalink / raw)
To: linux-btrace
stop_tracers modifies tp->is_done and thus must signal the condition
variable tracer_wait_unblock is waiting on to monitor tp->is_done.
Not doing so might cause the tool to deadlock if stop_tracers is
called while a tracer thread is in tracer_wait_unblock.
Signed-off-by: Robert Schiele <rschiele@gmail.com>
---
blktrace.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/blktrace.c b/blktrace.c
index 7e64c94..3c8fb4c 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -1913,6 +1913,7 @@ static void stop_tracers(void)
struct tracer *tp = list_entry(p, struct tracer, head);
tp->is_done = 1;
}
+ pthread_cond_broadcast(&mt_cond);
}
static void del_tracers(void)
--
1.8.4.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] signal condition variable at end of stop_tracers
2014-09-08 7:38 [PATCH] signal condition variable at end of stop_tracers Robert Schiele
@ 2014-09-08 14:16 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2014-09-08 14:16 UTC (permalink / raw)
To: linux-btrace
On 09/08/2014 01:38 AM, Robert Schiele wrote:
> stop_tracers modifies tp->is_done and thus must signal the condition
> variable tracer_wait_unblock is waiting on to monitor tp->is_done.
> Not doing so might cause the tool to deadlock if stop_tracers is
> called while a tracer thread is in tracer_wait_unblock.
>
> Signed-off-by: Robert Schiele <rschiele@gmail.com>
> ---
> blktrace.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/blktrace.c b/blktrace.c
> index 7e64c94..3c8fb4c 100644
> --- a/blktrace.c
> +++ b/blktrace.c
> @@ -1913,6 +1913,7 @@ static void stop_tracers(void)
> struct tracer *tp = list_entry(p, struct tracer, head);
> tp->is_done = 1;
> }
> + pthread_cond_broadcast(&mt_cond);
> }
>
> static void del_tracers(void)
>
Good catch! Applied.
--
Jens Axboe
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2014-09-08 14:16 ` Jens Axboe
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