* rcu: fix hlist_bl_set_first_rcu annotation @ 2013-01-30 19:07 Steven Whitehouse 2013-02-03 18:39 ` Paul E. McKenney 0 siblings, 1 reply; 6+ messages in thread From: Steven Whitehouse @ 2013-01-30 19:07 UTC (permalink / raw) To: Dipankar Sarma, Paul E. McKenney; +Cc: linux-kernel, adas Abhi noticed that we were getting a complaint from the RCU subsystem about access of an RCU protected list under the write side bit lock. This patch adds additional annotation to check both the RCU read lock and the write side bit lock before printing a message. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Reported-by: Abhijith Das <adas@redhat.com> Tested-by: Abhijith Das <adas@redhat.com> diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 31f9d75..2eb8855 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) __bit_spin_unlock(0, (unsigned long *)b); } +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) +{ + return bit_spin_is_locked(0, (unsigned long *)b); +} + /** * hlist_bl_for_each_entry - iterate over list of given type * @tpos: the type * to use as a loop cursor. diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h index cf1244f..4f216c5 100644 --- a/include/linux/rculist_bl.h +++ b/include/linux/rculist_bl.h @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) { return (struct hlist_bl_node *) - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); } /** ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: rcu: fix hlist_bl_set_first_rcu annotation 2013-01-30 19:07 rcu: fix hlist_bl_set_first_rcu annotation Steven Whitehouse @ 2013-02-03 18:39 ` Paul E. McKenney 2013-02-15 0:01 ` Andrew Price 2013-03-12 9:44 ` Steven Whitehouse 0 siblings, 2 replies; 6+ messages in thread From: Paul E. McKenney @ 2013-02-03 18:39 UTC (permalink / raw) To: Steven Whitehouse; +Cc: Dipankar Sarma, linux-kernel, adas, hch, npiggin On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: > > Abhi noticed that we were getting a complaint from the RCU subsystem > about access of an RCU protected list under the write side bit lock. > This patch adds additional annotation to check both the RCU read > lock and the write side bit lock before printing a message. > > Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> > Reported-by: Abhijith Das <adas@redhat.com> > Tested-by: Abhijith Das <adas@redhat.com> Looks plausible to me on first glance, copying Nick Piggin and Christoph Hellwig. If they have no objections, I will queue this. Thanx, Paul > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > index 31f9d75..2eb8855 100644 > --- a/include/linux/list_bl.h > +++ b/include/linux/list_bl.h > @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) > __bit_spin_unlock(0, (unsigned long *)b); > } > > +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) > +{ > + return bit_spin_is_locked(0, (unsigned long *)b); > +} > + > /** > * hlist_bl_for_each_entry - iterate over list of given type > * @tpos: the type * to use as a loop cursor. > diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h > index cf1244f..4f216c5 100644 > --- a/include/linux/rculist_bl.h > +++ b/include/linux/rculist_bl.h > @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, > static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) > { > return (struct hlist_bl_node *) > - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); > + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); > } > > /** > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: rcu: fix hlist_bl_set_first_rcu annotation 2013-02-03 18:39 ` Paul E. McKenney @ 2013-02-15 0:01 ` Andrew Price 2013-02-15 0:47 ` Paul E. McKenney 2013-03-12 9:44 ` Steven Whitehouse 1 sibling, 1 reply; 6+ messages in thread From: Andrew Price @ 2013-02-15 0:01 UTC (permalink / raw) To: paulmck; +Cc: Steven Whitehouse, Dipankar Sarma, linux-kernel, adas, hch, npiggin Hi, On 03/02/13 18:39, Paul E. McKenney wrote: > On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: >> >> Abhi noticed that we were getting a complaint from the RCU subsystem >> about access of an RCU protected list under the write side bit lock. >> This patch adds additional annotation to check both the RCU read >> lock and the write side bit lock before printing a message. >> >> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> >> Reported-by: Abhijith Das <adas@redhat.com> >> Tested-by: Abhijith Das <adas@redhat.com> > > Looks plausible to me on first glance, copying Nick Piggin and Christoph > Hellwig. If they have no objections, I will queue this. > > Thanx, Paul Has this had any attention yet? I'm also seeing the complaint quite frequently: [ 68.738811] =============================== [ 68.741380] [ INFO: suspicious RCU usage. ] [ 68.748785] 3.8.0-0.rc7.git1.1.fc19.x86_64 #1 Not tainted [ 68.750841] ------------------------------- [ 68.752418] include/linux/rculist_bl.h:23 suspicious rcu_dereference_check() usage! [ 68.755264] [ 68.755264] other info that might help us debug this: [ 68.755264] [ 68.758030] [ 68.758030] rcu_scheduler_active = 1, debug_locks = 0 [ 68.760316] 1 lock held by mount/476: [ 68.761896] #0: (&type->s_umount_key#38/1){+.+.+.}, at: [<ffffffff811dbbee>] sget+0x39e/0x670 [ 68.767115] [ 68.767115] stack backtrace: [ 68.769529] Pid: 476, comm: mount Not tainted 3.8.0-0.rc7.git1.1.fc19.x86_64 #1 [ 68.772095] Call Trace: [ 68.772995] [<ffffffff810d73b7>] lockdep_rcu_suspicious+0xe7/0x120 [ 68.775184] [<ffffffffa00e3238>] search_bucket+0x118/0x160 [gfs2] [ 68.777559] [<ffffffffa00e47c3>] gfs2_glock_get+0x603/0x7b0 [gfs2] [ 68.780749] [<ffffffffa00e41c5>] ? gfs2_glock_get+0x5/0x7b0 [gfs2] [ 68.784173] [<ffffffffa00e6db9>] gfs2_glock_nq_num+0x29/0x90 [gfs2] [ 68.786551] [<ffffffffa00f2b79>] gfs2_mount+0x869/0xf30 [gfs2] [ 68.788672] [<ffffffff810ad428>] ? sched_clock_cpu+0xa8/0x100 [ 68.790739] [<ffffffff810d561d>] ? trace_hardirqs_off+0xd/0x10 [ 68.793042] [<ffffffff810ad56f>] ? local_clock+0x5f/0x70 [ 68.794940] [<ffffffff81702500>] ? __mutex_unlock_slowpath+0x80/0x170 [ 68.798236] [<ffffffff811dcb49>] mount_fs+0x39/0x1b0 [ 68.800409] [<ffffffff811879c0>] ? __alloc_percpu+0x10/0x20 [ 68.803692] [<ffffffff811fa8e3>] vfs_kern_mount+0x63/0xf0 [ 68.806773] [<ffffffff811fcfb5>] do_mount+0x205/0xa90 [ 68.809669] [<ffffffff8118c8ec>] ? might_fault+0x5c/0xb0 [ 68.812717] [<ffffffff811819fb>] ? strndup_user+0x4b/0xf0 [ 68.816066] [<ffffffff811fd8c3>] sys_mount+0x83/0xc0 [ 68.818284] [<ffffffff8170ead9>] system_call_fastpath+0x16/0x1b It would be good to have this silenced for 3.8 but I think there's not long to go. Thanks, Andy >> diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h >> index 31f9d75..2eb8855 100644 >> --- a/include/linux/list_bl.h >> +++ b/include/linux/list_bl.h >> @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) >> __bit_spin_unlock(0, (unsigned long *)b); >> } >> >> +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) >> +{ >> + return bit_spin_is_locked(0, (unsigned long *)b); >> +} >> + >> /** >> * hlist_bl_for_each_entry - iterate over list of given type >> * @tpos: the type * to use as a loop cursor. >> diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h >> index cf1244f..4f216c5 100644 >> --- a/include/linux/rculist_bl.h >> +++ b/include/linux/rculist_bl.h >> @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, >> static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) >> { >> return (struct hlist_bl_node *) >> - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); >> + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); >> } >> >> /** >> >> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: rcu: fix hlist_bl_set_first_rcu annotation 2013-02-15 0:01 ` Andrew Price @ 2013-02-15 0:47 ` Paul E. McKenney 0 siblings, 0 replies; 6+ messages in thread From: Paul E. McKenney @ 2013-02-15 0:47 UTC (permalink / raw) To: Andrew Price Cc: Steven Whitehouse, Dipankar Sarma, linux-kernel, adas, hch, npiggin On Fri, Feb 15, 2013 at 12:01:30AM +0000, Andrew Price wrote: > Hi, > > On 03/02/13 18:39, Paul E. McKenney wrote: > >On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: > >> > >>Abhi noticed that we were getting a complaint from the RCU subsystem > >>about access of an RCU protected list under the write side bit lock. > >>This patch adds additional annotation to check both the RCU read > >>lock and the write side bit lock before printing a message. > >> > >>Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> > >>Reported-by: Abhijith Das <adas@redhat.com> > >>Tested-by: Abhijith Das <adas@redhat.com> > > > >Looks plausible to me on first glance, copying Nick Piggin and Christoph > >Hellwig. If they have no objections, I will queue this. > > > > Thanx, Paul > > Has this had any attention yet? I'm also seeing the complaint quite > frequently: > > [ 68.738811] =============================== > [ 68.741380] [ INFO: suspicious RCU usage. ] > [ 68.748785] 3.8.0-0.rc7.git1.1.fc19.x86_64 #1 Not tainted > [ 68.750841] ------------------------------- > [ 68.752418] include/linux/rculist_bl.h:23 suspicious > rcu_dereference_check() usage! > [ 68.755264] > [ 68.755264] other info that might help us debug this: > [ 68.755264] > [ 68.758030] > [ 68.758030] rcu_scheduler_active = 1, debug_locks = 0 > [ 68.760316] 1 lock held by mount/476: > [ 68.761896] #0: (&type->s_umount_key#38/1){+.+.+.}, at: > [<ffffffff811dbbee>] sget+0x39e/0x670 > [ 68.767115] > [ 68.767115] stack backtrace: > [ 68.769529] Pid: 476, comm: mount Not tainted > 3.8.0-0.rc7.git1.1.fc19.x86_64 #1 > [ 68.772095] Call Trace: > [ 68.772995] [<ffffffff810d73b7>] lockdep_rcu_suspicious+0xe7/0x120 > [ 68.775184] [<ffffffffa00e3238>] search_bucket+0x118/0x160 [gfs2] > [ 68.777559] [<ffffffffa00e47c3>] gfs2_glock_get+0x603/0x7b0 [gfs2] > [ 68.780749] [<ffffffffa00e41c5>] ? gfs2_glock_get+0x5/0x7b0 [gfs2] > [ 68.784173] [<ffffffffa00e6db9>] gfs2_glock_nq_num+0x29/0x90 [gfs2] > [ 68.786551] [<ffffffffa00f2b79>] gfs2_mount+0x869/0xf30 [gfs2] > [ 68.788672] [<ffffffff810ad428>] ? sched_clock_cpu+0xa8/0x100 > [ 68.790739] [<ffffffff810d561d>] ? trace_hardirqs_off+0xd/0x10 > [ 68.793042] [<ffffffff810ad56f>] ? local_clock+0x5f/0x70 > [ 68.794940] [<ffffffff81702500>] ? __mutex_unlock_slowpath+0x80/0x170 > [ 68.798236] [<ffffffff811dcb49>] mount_fs+0x39/0x1b0 > [ 68.800409] [<ffffffff811879c0>] ? __alloc_percpu+0x10/0x20 > [ 68.803692] [<ffffffff811fa8e3>] vfs_kern_mount+0x63/0xf0 > [ 68.806773] [<ffffffff811fcfb5>] do_mount+0x205/0xa90 > [ 68.809669] [<ffffffff8118c8ec>] ? might_fault+0x5c/0xb0 > [ 68.812717] [<ffffffff811819fb>] ? strndup_user+0x4b/0xf0 > [ 68.816066] [<ffffffff811fd8c3>] sys_mount+0x83/0xc0 > [ 68.818284] [<ffffffff8170ead9>] system_call_fastpath+0x16/0x1b > > It would be good to have this silenced for 3.8 but I think there's > not long to go. I have queued this, thank you. 3.8 is getting close to the end, but there is always -stable if the 3.8 series is of particular interest for this bug. Thanx, Paul > Thanks, > Andy > > >>diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > >>index 31f9d75..2eb8855 100644 > >>--- a/include/linux/list_bl.h > >>+++ b/include/linux/list_bl.h > >>@@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) > >> __bit_spin_unlock(0, (unsigned long *)b); > >> } > >> > >>+static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) > >>+{ > >>+ return bit_spin_is_locked(0, (unsigned long *)b); > >>+} > >>+ > >> /** > >> * hlist_bl_for_each_entry - iterate over list of given type > >> * @tpos: the type * to use as a loop cursor. > >>diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h > >>index cf1244f..4f216c5 100644 > >>--- a/include/linux/rculist_bl.h > >>+++ b/include/linux/rculist_bl.h > >>@@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, > >> static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) > >> { > >> return (struct hlist_bl_node *) > >>- ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); > >>+ ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); > >> } > >> > >> /** > >> > >> > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: rcu: fix hlist_bl_set_first_rcu annotation 2013-02-03 18:39 ` Paul E. McKenney 2013-02-15 0:01 ` Andrew Price @ 2013-03-12 9:44 ` Steven Whitehouse 2013-03-12 12:46 ` Paul E. McKenney 1 sibling, 1 reply; 6+ messages in thread From: Steven Whitehouse @ 2013-03-12 9:44 UTC (permalink / raw) To: paulmck; +Cc: Dipankar Sarma, linux-kernel, adas, hch, npiggin Hi, On Sun, 2013-02-03 at 10:39 -0800, Paul E. McKenney wrote: > On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: > > > > Abhi noticed that we were getting a complaint from the RCU subsystem > > about access of an RCU protected list under the write side bit lock. > > This patch adds additional annotation to check both the RCU read > > lock and the write side bit lock before printing a message. > > > > Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> > > Reported-by: Abhijith Das <adas@redhat.com> > > Tested-by: Abhijith Das <adas@redhat.com> > > Looks plausible to me on first glance, copying Nick Piggin and Christoph > Hellwig. If they have no objections, I will queue this. > > Thanx, Paul > Just a quick query to see what happened to this patch... it doesn't appear to have landed in Linus' tree yet, and I can't spot it in your git trees at korg either, Steve. > > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > > index 31f9d75..2eb8855 100644 > > --- a/include/linux/list_bl.h > > +++ b/include/linux/list_bl.h > > @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) > > __bit_spin_unlock(0, (unsigned long *)b); > > } > > > > +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) > > +{ > > + return bit_spin_is_locked(0, (unsigned long *)b); > > +} > > + > > /** > > * hlist_bl_for_each_entry - iterate over list of given type > > * @tpos: the type * to use as a loop cursor. > > diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h > > index cf1244f..4f216c5 100644 > > --- a/include/linux/rculist_bl.h > > +++ b/include/linux/rculist_bl.h > > @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, > > static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) > > { > > return (struct hlist_bl_node *) > > - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); > > + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); > > } > > > > /** > > > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: rcu: fix hlist_bl_set_first_rcu annotation 2013-03-12 9:44 ` Steven Whitehouse @ 2013-03-12 12:46 ` Paul E. McKenney 0 siblings, 0 replies; 6+ messages in thread From: Paul E. McKenney @ 2013-03-12 12:46 UTC (permalink / raw) To: Steven Whitehouse; +Cc: Dipankar Sarma, linux-kernel, adas, hch, npiggin On Tue, Mar 12, 2013 at 09:44:29AM +0000, Steven Whitehouse wrote: > Hi, > > On Sun, 2013-02-03 at 10:39 -0800, Paul E. McKenney wrote: > > On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: > > > > > > Abhi noticed that we were getting a complaint from the RCU subsystem > > > about access of an RCU protected list under the write side bit lock. > > > This patch adds additional annotation to check both the RCU read > > > lock and the write side bit lock before printing a message. > > > > > > Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> > > > Reported-by: Abhijith Das <adas@redhat.com> > > > Tested-by: Abhijith Das <adas@redhat.com> > > > > Looks plausible to me on first glance, copying Nick Piggin and Christoph > > Hellwig. If they have no objections, I will queue this. > > > > Thanx, Paul > > > > Just a quick query to see what happened to this patch... it doesn't > appear to have landed in Linus' tree yet, and I can't spot it in your > git trees at korg either, Hello, Steve, I have queued it for 3.10, and will push it to -rcu shortly. Thanx, Paul > Steve. > > > > > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > > > index 31f9d75..2eb8855 100644 > > > --- a/include/linux/list_bl.h > > > +++ b/include/linux/list_bl.h > > > @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) > > > __bit_spin_unlock(0, (unsigned long *)b); > > > } > > > > > > +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) > > > +{ > > > + return bit_spin_is_locked(0, (unsigned long *)b); > > > +} > > > + > > > /** > > > * hlist_bl_for_each_entry - iterate over list of given type > > > * @tpos: the type * to use as a loop cursor. > > > diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h > > > index cf1244f..4f216c5 100644 > > > --- a/include/linux/rculist_bl.h > > > +++ b/include/linux/rculist_bl.h > > > @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, > > > static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) > > > { > > > return (struct hlist_bl_node *) > > > - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); > > > + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); > > > } > > > > > > /** > > > > > > > > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-03-12 12:47 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2013-01-30 19:07 rcu: fix hlist_bl_set_first_rcu annotation Steven Whitehouse 2013-02-03 18:39 ` Paul E. McKenney 2013-02-15 0:01 ` Andrew Price 2013-02-15 0:47 ` Paul E. McKenney 2013-03-12 9:44 ` Steven Whitehouse 2013-03-12 12:46 ` Paul E. McKenney
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