* Re: [dm-devel] [PATCH 2/2] realtime: avoid BUG when the list is not locked [not found] <alpine.LRH.2.02.1911110853100.30532@file01.intranet.prod.int.rdu2.redhat.com> @ 2019-11-12 9:10 ` Daniel Wagner 2019-11-12 11:21 ` Mikulas Patocka 0 siblings, 1 reply; 3+ messages in thread From: Daniel Wagner @ 2019-11-12 9:10 UTC (permalink / raw) To: Mikulas Patocka Cc: Mike Snitzer, Scott Wood, dm-devel, Nikos Tsironis, Ilias Tsitsimpis, linux-rt-users, tglx, bigeasy [cc: linux-user-rt, Thomas and Sebastian] On Mon, Nov 11, 2019 at 08:59:44AM -0500, Mikulas Patocka wrote: > list_bl.h would crash with BUG() if we used it without locking. > dm-snapshot uses its own locking on readltime kernels, so to avoid this > BUG, we must set LIST_BL_LOCKMASK = 0. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > Index: linux-rt-devel/include/linux/list_bl.h > =================================================================== > --- linux-rt-devel.orig/include/linux/list_bl.h 2019-11-07 14:01:51.000000000 +0100 > +++ linux-rt-devel/include/linux/list_bl.h 2019-11-08 10:12:49.000000000 +0100 > @@ -19,7 +19,7 @@ > * some fast and compact auxiliary data. > */ > > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > +#if (defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)) && !defined(CONFIG_PREEMPT_RT_BASE) CONFIG_PREEMPT_RT_BASE is only available in the out of tree -rt patch set, therefore I assume it's not for mainline, right? > #define LIST_BL_LOCKMASK 1UL > #else > #define LIST_BL_LOCKMASK 0UL > @@ -161,9 +161,6 @@ static inline void hlist_bl_lock(struct > bit_spin_lock(0, (unsigned long *)b); > #else > raw_spin_lock(&b->lock); > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > - __set_bit(0, (unsigned long *)b); > -#endif > #endif > } > > @@ -172,9 +169,6 @@ static inline void hlist_bl_unlock(struc > #ifndef CONFIG_PREEMPT_RT_BASE > __bit_spin_unlock(0, (unsigned long *)b); > #else > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > - __clear_bit(0, (unsigned long *)b); > -#endif > raw_spin_unlock(&b->lock); > #endif > } > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel > Thanks, Daniel ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dm-devel] [PATCH 2/2] realtime: avoid BUG when the list is not locked 2019-11-12 9:10 ` [dm-devel] [PATCH 2/2] realtime: avoid BUG when the list is not locked Daniel Wagner @ 2019-11-12 11:21 ` Mikulas Patocka 2019-11-12 11:39 ` Sebastian Andrzej Siewior 0 siblings, 1 reply; 3+ messages in thread From: Mikulas Patocka @ 2019-11-12 11:21 UTC (permalink / raw) To: Daniel Wagner Cc: Mike Snitzer, Scott Wood, dm-devel, Nikos Tsironis, Ilias Tsitsimpis, linux-rt-users, tglx, bigeasy On Tue, 12 Nov 2019, Daniel Wagner wrote: > [cc: linux-user-rt, Thomas and Sebastian] > > On Mon, Nov 11, 2019 at 08:59:44AM -0500, Mikulas Patocka wrote: > > list_bl.h would crash with BUG() if we used it without locking. > > dm-snapshot uses its own locking on readltime kernels, so to avoid this > > BUG, we must set LIST_BL_LOCKMASK = 0. > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > > > Index: linux-rt-devel/include/linux/list_bl.h > > =================================================================== > > --- linux-rt-devel.orig/include/linux/list_bl.h 2019-11-07 14:01:51.000000000 +0100 > > +++ linux-rt-devel/include/linux/list_bl.h 2019-11-08 10:12:49.000000000 +0100 > > @@ -19,7 +19,7 @@ > > * some fast and compact auxiliary data. > > */ > > > > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > > +#if (defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)) && !defined(CONFIG_PREEMPT_RT_BASE) > > CONFIG_PREEMPT_RT_BASE is only available in the out of tree -rt patch > set, therefore I assume it's not for mainline, right? Yes - this is intended to be applied to the realtime patchset. Mikulas > > #define LIST_BL_LOCKMASK 1UL > > #else > > #define LIST_BL_LOCKMASK 0UL > > @@ -161,9 +161,6 @@ static inline void hlist_bl_lock(struct > > bit_spin_lock(0, (unsigned long *)b); > > #else > > raw_spin_lock(&b->lock); > > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > > - __set_bit(0, (unsigned long *)b); > > -#endif > > #endif > > } > > > > @@ -172,9 +169,6 @@ static inline void hlist_bl_unlock(struc > > #ifndef CONFIG_PREEMPT_RT_BASE > > __bit_spin_unlock(0, (unsigned long *)b); > > #else > > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > > - __clear_bit(0, (unsigned long *)b); > > -#endif > > raw_spin_unlock(&b->lock); > > #endif > > } > > > > -- > > dm-devel mailing list > > dm-devel@redhat.com > > https://www.redhat.com/mailman/listinfo/dm-devel > > > > Thanks, > Daniel > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dm-devel] [PATCH 2/2] realtime: avoid BUG when the list is not locked 2019-11-12 11:21 ` Mikulas Patocka @ 2019-11-12 11:39 ` Sebastian Andrzej Siewior 0 siblings, 0 replies; 3+ messages in thread From: Sebastian Andrzej Siewior @ 2019-11-12 11:39 UTC (permalink / raw) To: Mikulas Patocka Cc: Daniel Wagner, Mike Snitzer, Scott Wood, dm-devel, Nikos Tsironis, Ilias Tsitsimpis, linux-rt-users, tglx On 2019-11-12 06:21:57 [-0500], Mikulas Patocka wrote: > > CONFIG_PREEMPT_RT_BASE is only available in the out of tree -rt patch > > set, therefore I assume it's not for mainline, right? > > Yes - this is intended to be applied to the realtime patchset. In that case please repost it and Cc tglx and myself and add the RT tag after PATCH. Please make sure it applies and fixes a problem in the latest available RT kernel. Please state the problem on RT and how it is solved. > Mikulas Sebastian ^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-11-12 9:10 ` [dm-devel] [PATCH 2/2] realtime: avoid BUG when the list is not locked Daniel Wagner
2019-11-12 11:21 ` Mikulas Patocka
2019-11-12 11:39 ` Sebastian Andrzej Siewior
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