* [PATCH -tip] rcu: fix lockdep for tracepoint
@ 2010-03-16 9:00 Lai Jiangshan
2010-03-16 13:08 ` Mathieu Desnoyers
2010-03-16 14:47 ` [tip:core/urgent] rcu: Fix tracepoints & lockdep false positive tip-bot for Lai Jiangshan
0 siblings, 2 replies; 4+ messages in thread
From: Lai Jiangshan @ 2010-03-16 9:00 UTC (permalink / raw)
To: Ingo Molnar, Paul E. McKenney, Mathieu Desnoyers, LKML
tracepoint.h use rcu_dereference(), it triggers this warning:
[ 0.701161] ===================================================
[ 0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
[ 0.702716] ---------------------------------------------------
[ 0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
[ 0.703971]
[ 0.703990] other info that might help us debug this:
[ 0.703993]
[ 0.705590]
[ 0.705604] rcu_scheduler_active = 1, debug_locks = 0
[ 0.706712] 1 lock held by swapper/1:
[ 0.707229] #0: (cpu_add_remove_lock){+.+.+.}, at: [<c0142f54>] cpu_maps_update_begin+0x14/0x20
[ 0.710097]
[ 0.710106] stack backtrace:
[ 0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
[ 0.713231] Call Trace:
[ 0.713997] [<c017174d>] lockdep_rcu_dereference+0x9d/0xb0
[ 0.714746] [<c015a117>] create_workqueue_thread+0x107/0x110
[ 0.715353] [<c015aee0>] ? worker_thread+0x0/0x340
[ 0.715845] [<c015a8e8>] __create_workqueue_key+0x138/0x240
[ 0.716427] [<c0142f92>] ? cpu_maps_update_done+0x12/0x20
[ 0.717012] [<c086b12f>] init_workqueues+0x6f/0x80
[ 0.717530] [<c08576d2>] kernel_init+0x102/0x1f0
[ 0.717570] [<c08575d0>] ? kernel_init+0x0/0x1f0
[ 0.718944] [<c01030fa>] kernel_thread_helper+0x6/0x10
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index f59604e..78b4bd3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -49,7 +49,7 @@ struct tracepoint {
void **it_func; \
\
rcu_read_lock_sched_notrace(); \
- it_func = rcu_dereference((tp)->funcs); \
+ it_func = rcu_dereference_sched((tp)->funcs); \
if (it_func) { \
do { \
((void(*)(proto))(*it_func))(args); \
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH -tip] rcu: fix lockdep for tracepoint
2010-03-16 9:00 [PATCH -tip] rcu: fix lockdep for tracepoint Lai Jiangshan
@ 2010-03-16 13:08 ` Mathieu Desnoyers
2010-03-16 13:31 ` Paul E. McKenney
2010-03-16 14:47 ` [tip:core/urgent] rcu: Fix tracepoints & lockdep false positive tip-bot for Lai Jiangshan
1 sibling, 1 reply; 4+ messages in thread
From: Mathieu Desnoyers @ 2010-03-16 13:08 UTC (permalink / raw)
To: Lai Jiangshan; +Cc: Ingo Molnar, Paul E. McKenney, LKML
* Lai Jiangshan (laijs@cn.fujitsu.com) wrote:
> tracepoint.h use rcu_dereference(), it triggers this warning:
>
> [ 0.701161] ===================================================
> [ 0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
> [ 0.702716] ---------------------------------------------------
> [ 0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
> [ 0.703971]
> [ 0.703990] other info that might help us debug this:
> [ 0.703993]
> [ 0.705590]
> [ 0.705604] rcu_scheduler_active = 1, debug_locks = 0
> [ 0.706712] 1 lock held by swapper/1:
> [ 0.707229] #0: (cpu_add_remove_lock){+.+.+.}, at: [<c0142f54>] cpu_maps_update_begin+0x14/0x20
> [ 0.710097]
> [ 0.710106] stack backtrace:
> [ 0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
> [ 0.713231] Call Trace:
> [ 0.713997] [<c017174d>] lockdep_rcu_dereference+0x9d/0xb0
> [ 0.714746] [<c015a117>] create_workqueue_thread+0x107/0x110
> [ 0.715353] [<c015aee0>] ? worker_thread+0x0/0x340
> [ 0.715845] [<c015a8e8>] __create_workqueue_key+0x138/0x240
> [ 0.716427] [<c0142f92>] ? cpu_maps_update_done+0x12/0x20
> [ 0.717012] [<c086b12f>] init_workqueues+0x6f/0x80
> [ 0.717530] [<c08576d2>] kernel_init+0x102/0x1f0
> [ 0.717570] [<c08575d0>] ? kernel_init+0x0/0x1f0
> [ 0.718944] [<c01030fa>] kernel_thread_helper+0x6/0x10
>
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Thanks Lai,
Mathieu
> ---
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index f59604e..78b4bd3 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -49,7 +49,7 @@ struct tracepoint {
> void **it_func; \
> \
> rcu_read_lock_sched_notrace(); \
> - it_func = rcu_dereference((tp)->funcs); \
> + it_func = rcu_dereference_sched((tp)->funcs); \
> if (it_func) { \
> do { \
> ((void(*)(proto))(*it_func))(args); \
>
--
Mathieu Desnoyers
Operating System Efficiency Consultant
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH -tip] rcu: fix lockdep for tracepoint
2010-03-16 13:08 ` Mathieu Desnoyers
@ 2010-03-16 13:31 ` Paul E. McKenney
0 siblings, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2010-03-16 13:31 UTC (permalink / raw)
To: Mathieu Desnoyers; +Cc: Lai Jiangshan, Ingo Molnar, LKML
On Tue, Mar 16, 2010 at 09:08:14AM -0400, Mathieu Desnoyers wrote:
> * Lai Jiangshan (laijs@cn.fujitsu.com) wrote:
> > tracepoint.h use rcu_dereference(), it triggers this warning:
> >
> > [ 0.701161] ===================================================
> > [ 0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
> > [ 0.702716] ---------------------------------------------------
> > [ 0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
> > [ 0.703971]
> > [ 0.703990] other info that might help us debug this:
> > [ 0.703993]
> > [ 0.705590]
> > [ 0.705604] rcu_scheduler_active = 1, debug_locks = 0
> > [ 0.706712] 1 lock held by swapper/1:
> > [ 0.707229] #0: (cpu_add_remove_lock){+.+.+.}, at: [<c0142f54>] cpu_maps_update_begin+0x14/0x20
> > [ 0.710097]
> > [ 0.710106] stack backtrace:
> > [ 0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
> > [ 0.713231] Call Trace:
> > [ 0.713997] [<c017174d>] lockdep_rcu_dereference+0x9d/0xb0
> > [ 0.714746] [<c015a117>] create_workqueue_thread+0x107/0x110
> > [ 0.715353] [<c015aee0>] ? worker_thread+0x0/0x340
> > [ 0.715845] [<c015a8e8>] __create_workqueue_key+0x138/0x240
> > [ 0.716427] [<c0142f92>] ? cpu_maps_update_done+0x12/0x20
> > [ 0.717012] [<c086b12f>] init_workqueues+0x6f/0x80
> > [ 0.717530] [<c08576d2>] kernel_init+0x102/0x1f0
> > [ 0.717570] [<c08575d0>] ? kernel_init+0x0/0x1f0
> > [ 0.718944] [<c01030fa>] kernel_thread_helper+0x6/0x10
> >
> > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
>
> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>
> Thanks Lai,
Me too!
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Mathieu
>
> > ---
> > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> > index f59604e..78b4bd3 100644
> > --- a/include/linux/tracepoint.h
> > +++ b/include/linux/tracepoint.h
> > @@ -49,7 +49,7 @@ struct tracepoint {
> > void **it_func; \
> > \
> > rcu_read_lock_sched_notrace(); \
> > - it_func = rcu_dereference((tp)->funcs); \
> > + it_func = rcu_dereference_sched((tp)->funcs); \
> > if (it_func) { \
> > do { \
> > ((void(*)(proto))(*it_func))(args); \
> >
>
> --
> Mathieu Desnoyers
> Operating System Efficiency Consultant
> EfficiOS Inc.
> http://www.efficios.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip:core/urgent] rcu: Fix tracepoints & lockdep false positive
2010-03-16 9:00 [PATCH -tip] rcu: fix lockdep for tracepoint Lai Jiangshan
2010-03-16 13:08 ` Mathieu Desnoyers
@ 2010-03-16 14:47 ` tip-bot for Lai Jiangshan
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Lai Jiangshan @ 2010-03-16 14:47 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, mathieu.desnoyers, hpa, mingo, paulmck, fweisbec,
rostedt, tglx, laijs, mingo
Commit-ID: 7f5b774275df8c76a959eae7488128b637fcbfc8
Gitweb: http://git.kernel.org/tip/7f5b774275df8c76a959eae7488128b637fcbfc8
Author: Lai Jiangshan <laijs@cn.fujitsu.com>
AuthorDate: Tue, 16 Mar 2010 17:00:29 +0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 16 Mar 2010 10:10:40 +0100
rcu: Fix tracepoints & lockdep false positive
tracepoint.h uses rcu_dereference(), which triggers this warning:
[ 0.701161] ===================================================
[ 0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
[ 0.702716] ---------------------------------------------------
[ 0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
[ 0.703971] [ 0.703990] other info that might help us debug this:
[ 0.703993]
[ 0.705590]
[ 0.705604] rcu_scheduler_active = 1, debug_locks = 0
[ 0.706712] 1 lock held by swapper/1:
[ 0.707229] #0: (cpu_add_remove_lock){+.+.+.}, at: [<c0142f54>] cpu_maps_update_begin+0x14/0x20
[ 0.710097]
[ 0.710106] stack backtrace:
[ 0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
[ 0.713231] Call Trace:
[ 0.713997] [<c017174d>] lockdep_rcu_dereference+0x9d/0xb0
[ 0.714746] [<c015a117>] create_workqueue_thread+0x107/0x110
[ 0.715353] [<c015aee0>] ? worker_thread+0x0/0x340
[ 0.715845] [<c015a8e8>] __create_workqueue_key+0x138/0x240
[ 0.716427] [<c0142f92>] ? cpu_maps_update_done+0x12/0x20
[ 0.717012] [<c086b12f>] init_workqueues+0x6f/0x80
[ 0.717530] [<c08576d2>] kernel_init+0x102/0x1f0
[ 0.717570] [<c08575d0>] ? kernel_init+0x0/0x1f0
[ 0.718944] [<c01030fa>] kernel_thread_helper+0x6/0x10
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B9F48AD.4000404@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/tracepoint.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index f59604e..78b4bd3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -49,7 +49,7 @@ struct tracepoint {
void **it_func; \
\
rcu_read_lock_sched_notrace(); \
- it_func = rcu_dereference((tp)->funcs); \
+ it_func = rcu_dereference_sched((tp)->funcs); \
if (it_func) { \
do { \
((void(*)(proto))(*it_func))(args); \
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2010-03-16 9:00 [PATCH -tip] rcu: fix lockdep for tracepoint Lai Jiangshan
2010-03-16 13:08 ` Mathieu Desnoyers
2010-03-16 13:31 ` Paul E. McKenney
2010-03-16 14:47 ` [tip:core/urgent] rcu: Fix tracepoints & lockdep false positive tip-bot for Lai Jiangshan
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