* Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk
2019-11-19 12:14 [PATCH] perf/core: Add SRCU annotation for pmus list walk Sebastian Andrzej Siewior
@ 2019-11-29 10:31 ` Sebastian Andrzej Siewior
2019-11-29 20:05 ` Joel Fernandes
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Sebastian Andrzej Siewior @ 2019-11-29 10:31 UTC (permalink / raw)
To: linux-kernel, Joel Fernandes, Paul E. McKenney
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
Thomas Gleixner
On 2019-11-19 13:14:29 [+0100], To linux-kernel@vger.kernel.org wrote:
> Since commit
> 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
>
> there is an additional check to ensure that a RCU related lock is held
> while the RCU list is iterated.
> This section holds the SRCU reader lock instead.
>
> Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
> acquired during the list traversal.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>
> I see the warning in in v5.4-rc during boot. For some reason I don't see
> it in tip/master during boot but "perf stat w" triggers it again (among
> other things).
ping.
> kernel/events/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 5224388872069..dbb3b26a55612 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10497,7 +10497,7 @@ static struct pmu *perf_init_event(struct perf_event *event)
> goto unlock;
> }
>
> - list_for_each_entry_rcu(pmu, &pmus, entry) {
> + list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
> ret = perf_try_init_event(pmu, event);
> if (!ret)
> goto unlock;
Sebastian
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk
2019-11-19 12:14 [PATCH] perf/core: Add SRCU annotation for pmus list walk Sebastian Andrzej Siewior
2019-11-29 10:31 ` Sebastian Andrzej Siewior
@ 2019-11-29 20:05 ` Joel Fernandes
2019-12-17 11:48 ` Sebastian Andrzej Siewior
2019-12-17 12:21 ` Peter Zijlstra
2019-12-17 12:39 ` [tip: perf/urgent] " tip-bot2 for Sebastian Andrzej Siewior
3 siblings, 1 reply; 7+ messages in thread
From: Joel Fernandes @ 2019-11-29 20:05 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: linux-kernel, Paul E. McKenney, Peter Zijlstra, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Thomas Gleixner
On Tue, Nov 19, 2019 at 01:14:29PM +0100, Sebastian Andrzej Siewior wrote:
> Since commit
> 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
>
> there is an additional check to ensure that a RCU related lock is held
> while the RCU list is iterated.
> This section holds the SRCU reader lock instead.
>
> Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
> acquired during the list traversal.
>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
thanks,
- Joel
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>
> I see the warning in in v5.4-rc during boot. For some reason I don't see
> it in tip/master during boot but "perf stat w" triggers it again (among
> other things).
>
> kernel/events/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 5224388872069..dbb3b26a55612 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10497,7 +10497,7 @@ static struct pmu *perf_init_event(struct perf_event *event)
> goto unlock;
> }
>
> - list_for_each_entry_rcu(pmu, &pmus, entry) {
> + list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
> ret = perf_try_init_event(pmu, event);
> if (!ret)
> goto unlock;
> --
> 2.24.0
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk
2019-11-29 20:05 ` Joel Fernandes
@ 2019-12-17 11:48 ` Sebastian Andrzej Siewior
0 siblings, 0 replies; 7+ messages in thread
From: Sebastian Andrzej Siewior @ 2019-12-17 11:48 UTC (permalink / raw)
To: Joel Fernandes
Cc: linux-kernel, Paul E. McKenney, Peter Zijlstra, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Thomas Gleixner
On 2019-11-29 15:05:22 [-0500], Joel Fernandes wrote:
> On Tue, Nov 19, 2019 at 01:14:29PM +0100, Sebastian Andrzej Siewior wrote:
> > Since commit
> > 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
> >
> > there is an additional check to ensure that a RCU related lock is held
> > while the RCU list is iterated.
> > This section holds the SRCU reader lock instead.
> >
> > Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
> > acquired during the list traversal.
> >
>
> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
>
> thanks,
>
> - Joel
>
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > ---
> >
> > I see the warning in in v5.4-rc during boot. For some reason I don't see
> > it in tip/master during boot but "perf stat w" triggers it again (among
> > other things).
kind ping
Sebastian
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk
2019-11-19 12:14 [PATCH] perf/core: Add SRCU annotation for pmus list walk Sebastian Andrzej Siewior
2019-11-29 10:31 ` Sebastian Andrzej Siewior
2019-11-29 20:05 ` Joel Fernandes
@ 2019-12-17 12:21 ` Peter Zijlstra
2019-12-17 13:03 ` Sebastian Andrzej Siewior
2019-12-17 12:39 ` [tip: perf/urgent] " tip-bot2 for Sebastian Andrzej Siewior
3 siblings, 1 reply; 7+ messages in thread
From: Peter Zijlstra @ 2019-12-17 12:21 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: linux-kernel, Joel Fernandes, Paul E. McKenney, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Thomas Gleixner
On Tue, Nov 19, 2019 at 01:14:29PM +0100, Sebastian Andrzej Siewior wrote:
> Since commit
> 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
>
> there is an additional check to ensure that a RCU related lock is held
> while the RCU list is iterated.
> This section holds the SRCU reader lock instead.
>
> Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
> acquired during the list traversal.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>
> I see the warning in in v5.4-rc during boot. For some reason I don't see
> it in tip/master during boot but "perf stat w" triggers it again (among
> other things).
>
> kernel/events/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 5224388872069..dbb3b26a55612 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10497,7 +10497,7 @@ static struct pmu *perf_init_event(struct perf_event *event)
> goto unlock;
> }
>
> - list_for_each_entry_rcu(pmu, &pmus, entry) {
> + list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
That's a bit obnoxious, but ok, I suppose.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk
2019-12-17 12:21 ` Peter Zijlstra
@ 2019-12-17 13:03 ` Sebastian Andrzej Siewior
0 siblings, 0 replies; 7+ messages in thread
From: Sebastian Andrzej Siewior @ 2019-12-17 13:03 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, Joel Fernandes, Paul E. McKenney, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Thomas Gleixner
On 2019-12-17 13:21:52 [+0100], Peter Zijlstra wrote:
> That's a bit obnoxious, but ok, I suppose.
If you want something else, feel free. I asked a few times for a
statement from the RCU division and all I got were ACKs from Joel which
implies that this is what they want. So…
Sebastian
^ permalink raw reply [flat|nested] 7+ messages in thread
* [tip: perf/urgent] perf/core: Add SRCU annotation for pmus list walk
2019-11-19 12:14 [PATCH] perf/core: Add SRCU annotation for pmus list walk Sebastian Andrzej Siewior
` (2 preceding siblings ...)
2019-12-17 12:21 ` Peter Zijlstra
@ 2019-12-17 12:39 ` tip-bot2 for Sebastian Andrzej Siewior
3 siblings, 0 replies; 7+ messages in thread
From: tip-bot2 for Sebastian Andrzej Siewior @ 2019-12-17 12:39 UTC (permalink / raw)
To: linux-tip-commits
Cc: Sebastian Andrzej Siewior, Peter Zijlstra (Intel),
Joel Fernandes (Google),
x86, LKML
The following commit has been merged into the perf/urgent branch of tip:
Commit-ID: 9f0bff1180efc9ea988fed3fd93da7647151ac8b
Gitweb: https://git.kernel.org/tip/9f0bff1180efc9ea988fed3fd93da7647151ac8b
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Tue, 19 Nov 2019 13:14:29 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 17 Dec 2019 13:32:46 +01:00
perf/core: Add SRCU annotation for pmus list walk
Since commit
28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
there is an additional check to ensure that a RCU related lock is held
while the RCU list is iterated.
This section holds the SRCU reader lock instead.
Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
acquired during the list traversal.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lkml.kernel.org/r/20191119121429.zhcubzdhm672zasg@linutronix.de
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ff86d5..a1f8bde 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10523,7 +10523,7 @@ again:
goto unlock;
}
- list_for_each_entry_rcu(pmu, &pmus, entry) {
+ list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
ret = perf_try_init_event(pmu, event);
if (!ret)
goto unlock;
^ permalink raw reply [flat|nested] 7+ messages in thread