| Message ID | 201802082043.FFJ39503.SVQFFFOJMHLOtO@I-love.SAKURA.ne.jp (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 8.02.2018 13:43, Tetsuo Handa wrote: >>From 361d37a7d36978020dfb4c11ec1f4800937ccb68 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Date: Thu, 8 Feb 2018 10:35:35 +0900 > Subject: [PATCH v2] lockdep: Fix fs_reclaim warning. > > Dave Jones reported fs_reclaim lockdep warnings. > > ============================================ > WARNING: possible recursive locking detected > 4.15.0-rc9-backup-debug+ #1 Not tainted > -------------------------------------------- > sshd/24800 is trying to acquire lock: > (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > but task is already holding lock: > (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(fs_reclaim); > lock(fs_reclaim); > > *** DEADLOCK *** > > May be due to missing lock nesting notation > > 2 locks held by sshd/24800: > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000001a069652>] tcp_sendmsg+0x19/0x40 > #1: (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > stack backtrace: > CPU: 3 PID: 24800 Comm: sshd Not tainted 4.15.0-rc9-backup-debug+ #1 > Call Trace: > dump_stack+0xbc/0x13f > __lock_acquire+0xa09/0x2040 > lock_acquire+0x12e/0x350 > fs_reclaim_acquire.part.102+0x29/0x30 > kmem_cache_alloc+0x3d/0x2c0 > alloc_extent_state+0xa7/0x410 > __clear_extent_bit+0x3ea/0x570 > try_release_extent_mapping+0x21a/0x260 > __btrfs_releasepage+0xb0/0x1c0 > btrfs_releasepage+0x161/0x170 > try_to_release_page+0x162/0x1c0 > shrink_page_list+0x1d5a/0x2fb0 > shrink_inactive_list+0x451/0x940 > shrink_node_memcg.constprop.88+0x4c9/0x5e0 > shrink_node+0x12d/0x260 > try_to_free_pages+0x418/0xaf0 > __alloc_pages_slowpath+0x976/0x1790 > __alloc_pages_nodemask+0x52c/0x5c0 > new_slab+0x374/0x3f0 > ___slab_alloc.constprop.81+0x47e/0x5a0 > __slab_alloc.constprop.80+0x32/0x60 > __kmalloc_track_caller+0x267/0x310 > __kmalloc_reserve.isra.40+0x29/0x80 > __alloc_skb+0xee/0x390 > sk_stream_alloc_skb+0xb8/0x340 > tcp_sendmsg_locked+0x8e6/0x1d30 > tcp_sendmsg+0x27/0x40 > inet_sendmsg+0xd0/0x310 > sock_write_iter+0x17a/0x240 > __vfs_write+0x2ab/0x380 > vfs_write+0xfb/0x260 > SyS_write+0xb6/0x140 > do_syscall_64+0x1e5/0xc05 > entry_SYSCALL64_slow_path+0x25/0x25 > I think I've hit another incarnation of that one. The call stack is: http://paste.opensuse.org/3f22d013 The cleaned up callstack of all the ? entries look like: __lock_acquire+0x2d8a/0x4b70 lock_acquire+0x110/0x330 kmem_cache_alloc+0x29/0x2c0 __clear_extent_bit+0x488/0x800 try_release_extent_mapping+0x288/0x3c0 __btrfs_releasepage+0x6c/0x140 shrink_page_list+0x227e/0x3110 shrink_inactive_list+0x414/0xdb0 shrink_node_memcg+0x7c8/0x1250 shrink_node+0x2ae/0xb50 do_try_to_free_pages+0x2b1/0xe20 try_to_free_pages+0x205/0x570 __alloc_pages_nodemask+0xb91/0x2160 new_slab+0x27a/0x4e0 ___slab_alloc+0x355/0x610 __slab_alloc+0x4c/0xa0 kmem_cache_alloc+0x22d/0x2c0 mempool_alloc+0xe1/0x280 bio_alloc_bioset+0x1d7/0x830 ext4_mpage_readpages+0x99f/0x1000 <- __do_page_cache_readahead+0x4be/0x840 filemap_fault+0x8c8/0xfc0 ext4_filemap_fault+0x7d/0xb0 __do_fault+0x7a/0x150 __handle_mm_fault+0x1542/0x29d0 __do_page_fault+0x557/0xa30 async_page_fault+0x4c/0x60 There is no fs stacking going on here and that is 4.15-rc9. > This warning is caused by commit d92a8cfcb37ecd13 ("locking/lockdep: Rework > FS_RECLAIM annotation") which replaced lockdep_set_current_reclaim_state()/ > lockdep_clear_current_reclaim_state() in __perform_reclaim() and > lockdep_trace_alloc() in slab_pre_alloc_hook() with fs_reclaim_acquire()/ > fs_reclaim_release(). Since __kmalloc_reserve() from __alloc_skb() adds > __GFP_NOMEMALLOC | __GFP_NOWARN to gfp_mask, and all reclaim path simply > propagates __GFP_NOMEMALLOC, fs_reclaim_acquire() in slab_pre_alloc_hook() > is trying to grab the 'fake' lock again when __perform_reclaim() already > grabbed the 'fake' lock. > > The > > /* this guy won't enter reclaim */ > if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) > return false; > > test which causes slab_pre_alloc_hook() to try to grab the 'fake' lock > was added by commit cf40bd16fdad42c0 ("lockdep: annotate reclaim context > (__GFP_NOFS)"). But that test is outdated because PF_MEMALLOC thread won't > enter reclaim regardless of __GFP_NOMEMALLOC after commit 341ce06f69abfafa > ("page allocator: calculate the alloc_flags for allocation only once") > added the PF_MEMALLOC safeguard ( > > /* Avoid recursion of direct reclaim */ > if (p->flags & PF_MEMALLOC) > goto nopage; > > in __alloc_pages_slowpath()). > > Thus, let's fix outdated test by removing __GFP_NOMEMALLOC test and allow > __need_fs_reclaim() to return false. > > Reported-and-tested-by: Dave Jones <davej@codemonkey.org.uk> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Nick Piggin <npiggin@gmail.com> > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 81e18ce..19fb76b 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3590,7 +3590,7 @@ static bool __need_fs_reclaim(gfp_t gfp_mask) > return false; > > /* this guy won't enter reclaim */ > - if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) > + if (current->flags & PF_MEMALLOC) > return false; > > /* We're only interested __GFP_FS allocations for now */ > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Nikolay Borisov wrote: > I think I've hit another incarnation of that one. The call stack is: > http://paste.opensuse.org/3f22d013 > > The cleaned up callstack of all the ? entries look like: > > __lock_acquire+0x2d8a/0x4b70 > lock_acquire+0x110/0x330 > kmem_cache_alloc+0x29/0x2c0 > __clear_extent_bit+0x488/0x800 > try_release_extent_mapping+0x288/0x3c0 > __btrfs_releasepage+0x6c/0x140 > shrink_page_list+0x227e/0x3110 > shrink_inactive_list+0x414/0xdb0 > shrink_node_memcg+0x7c8/0x1250 > shrink_node+0x2ae/0xb50 > do_try_to_free_pages+0x2b1/0xe20 > try_to_free_pages+0x205/0x570 > __alloc_pages_nodemask+0xb91/0x2160 > new_slab+0x27a/0x4e0 > ___slab_alloc+0x355/0x610 > __slab_alloc+0x4c/0xa0 > kmem_cache_alloc+0x22d/0x2c0 > mempool_alloc+0xe1/0x280 Yes, for mempool_alloc() is adding __GFP_NOMEMALLOC | __GFP_NOWARN to gfp_mask. gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */ gfp_mask |= __GFP_NOWARN; /* failures are OK */ > bio_alloc_bioset+0x1d7/0x830 > ext4_mpage_readpages+0x99f/0x1000 <- > __do_page_cache_readahead+0x4be/0x840 > filemap_fault+0x8c8/0xfc0 > ext4_filemap_fault+0x7d/0xb0 > __do_fault+0x7a/0x150 > __handle_mm_fault+0x1542/0x29d0 > __do_page_fault+0x557/0xa30 > async_page_fault+0x4c/0x60 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Peter, are you OK with this patch? Tetsuo Handa wrote: > From 361d37a7d36978020dfb4c11ec1f4800937ccb68 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Date: Thu, 8 Feb 2018 10:35:35 +0900 > Subject: [PATCH v2] lockdep: Fix fs_reclaim warning. > > Dave Jones reported fs_reclaim lockdep warnings. > > ============================================ > WARNING: possible recursive locking detected > 4.15.0-rc9-backup-debug+ #1 Not tainted > -------------------------------------------- > sshd/24800 is trying to acquire lock: > (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > but task is already holding lock: > (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(fs_reclaim); > lock(fs_reclaim); > > *** DEADLOCK *** > > May be due to missing lock nesting notation > > 2 locks held by sshd/24800: > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000001a069652>] tcp_sendmsg+0x19/0x40 > #1: (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30 > > stack backtrace: > CPU: 3 PID: 24800 Comm: sshd Not tainted 4.15.0-rc9-backup-debug+ #1 > Call Trace: > dump_stack+0xbc/0x13f > __lock_acquire+0xa09/0x2040 > lock_acquire+0x12e/0x350 > fs_reclaim_acquire.part.102+0x29/0x30 > kmem_cache_alloc+0x3d/0x2c0 > alloc_extent_state+0xa7/0x410 > __clear_extent_bit+0x3ea/0x570 > try_release_extent_mapping+0x21a/0x260 > __btrfs_releasepage+0xb0/0x1c0 > btrfs_releasepage+0x161/0x170 > try_to_release_page+0x162/0x1c0 > shrink_page_list+0x1d5a/0x2fb0 > shrink_inactive_list+0x451/0x940 > shrink_node_memcg.constprop.88+0x4c9/0x5e0 > shrink_node+0x12d/0x260 > try_to_free_pages+0x418/0xaf0 > __alloc_pages_slowpath+0x976/0x1790 > __alloc_pages_nodemask+0x52c/0x5c0 > new_slab+0x374/0x3f0 > ___slab_alloc.constprop.81+0x47e/0x5a0 > __slab_alloc.constprop.80+0x32/0x60 > __kmalloc_track_caller+0x267/0x310 > __kmalloc_reserve.isra.40+0x29/0x80 > __alloc_skb+0xee/0x390 > sk_stream_alloc_skb+0xb8/0x340 > tcp_sendmsg_locked+0x8e6/0x1d30 > tcp_sendmsg+0x27/0x40 > inet_sendmsg+0xd0/0x310 > sock_write_iter+0x17a/0x240 > __vfs_write+0x2ab/0x380 > vfs_write+0xfb/0x260 > SyS_write+0xb6/0x140 > do_syscall_64+0x1e5/0xc05 > entry_SYSCALL64_slow_path+0x25/0x25 > > This warning is caused by commit d92a8cfcb37ecd13 ("locking/lockdep: Rework > FS_RECLAIM annotation") which replaced lockdep_set_current_reclaim_state()/ > lockdep_clear_current_reclaim_state() in __perform_reclaim() and > lockdep_trace_alloc() in slab_pre_alloc_hook() with fs_reclaim_acquire()/ > fs_reclaim_release(). Since __kmalloc_reserve() from __alloc_skb() adds > __GFP_NOMEMALLOC | __GFP_NOWARN to gfp_mask, and all reclaim path simply > propagates __GFP_NOMEMALLOC, fs_reclaim_acquire() in slab_pre_alloc_hook() > is trying to grab the 'fake' lock again when __perform_reclaim() already > grabbed the 'fake' lock. > > The > > /* this guy won't enter reclaim */ > if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) > return false; > > test which causes slab_pre_alloc_hook() to try to grab the 'fake' lock > was added by commit cf40bd16fdad42c0 ("lockdep: annotate reclaim context > (__GFP_NOFS)"). But that test is outdated because PF_MEMALLOC thread won't > enter reclaim regardless of __GFP_NOMEMALLOC after commit 341ce06f69abfafa > ("page allocator: calculate the alloc_flags for allocation only once") > added the PF_MEMALLOC safeguard ( > > /* Avoid recursion of direct reclaim */ > if (p->flags & PF_MEMALLOC) > goto nopage; > > in __alloc_pages_slowpath()). > > Thus, let's fix outdated test by removing __GFP_NOMEMALLOC test and allow > __need_fs_reclaim() to return false. > > Reported-and-tested-by: Dave Jones <davej@codemonkey.org.uk> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Nick Piggin <npiggin@gmail.com> > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 81e18ce..19fb76b 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3590,7 +3590,7 @@ static bool __need_fs_reclaim(gfp_t gfp_mask) > return false; > > /* this guy won't enter reclaim */ > - if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) > + if (current->flags & PF_MEMALLOC) > return false; > > /* We're only interested __GFP_FS allocations for now */ > -- > 1.8.3.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 81e18ce..19fb76b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3590,7 +3590,7 @@ static bool __need_fs_reclaim(gfp_t gfp_mask) return false; /* this guy won't enter reclaim */ - if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) + if (current->flags & PF_MEMALLOC) return false; /* We're only interested __GFP_FS allocations for now */