On 28.02.2017 16:56, Nikolay Borisov wrote:
> Hello,
>
> I've been running xfstest and I can reliably reproduce the following lockdep splat:
>
> [ 644.173373] =================================
> [ 644.174012] [ INFO: inconsistent lock state ]
> [ 644.174012] 4.10.0-nbor #134 Not tainted
> [ 644.174012] ---------------------------------
> [ 644.174012] inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
> [ 644.174012] fsstress/3365 [HC0[0]:SC0[0]:HE1:SE1] takes:
> [ 644.174012] (&xfs_nondir_ilock_class){++++?.}, at: [<ffffffff8136f231>] xfs_ilock+0x141/0x230
> [ 644.174012] {IN-RECLAIM_FS-W} state was registered at:
> [ 644.174012] __lock_acquire+0x62a/0x17c0
> [ 644.174012] lock_acquire+0xc5/0x220
> [ 644.174012] down_write_nested+0x4f/0x90
> [ 644.174012] xfs_ilock+0x141/0x230
> [ 644.174012] xfs_reclaim_inode+0x12a/0x320
> [ 644.174012] xfs_reclaim_inodes_ag+0x2c8/0x4e0
> [ 644.174012] xfs_reclaim_inodes_nr+0x33/0x40
> [ 644.174012] xfs_fs_free_cached_objects+0x19/0x20
> [ 644.174012] super_cache_scan+0x191/0x1a0
> [ 644.174012] shrink_slab+0x26f/0x5f0
> [ 644.174012] shrink_node+0xf9/0x2f0
> [ 644.174012] kswapd+0x356/0x920
> [ 644.174012] kthread+0x10c/0x140
> [ 644.174012] ret_from_fork+0x31/0x40
> [ 644.174012] irq event stamp: 173777
> [ 644.174012] hardirqs last enabled at (173777): [<ffffffff8105b440>] __local_bh_enable_ip+0x70/0xc0
> [ 644.174012] hardirqs last disabled at (173775): [<ffffffff8105b407>] __local_bh_enable_ip+0x37/0xc0
> [ 644.174012] softirqs last enabled at (173776): [<ffffffff81357e2a>] _xfs_buf_find+0x67a/0xb70
> [ 644.174012] softirqs last disabled at (173774): [<ffffffff81357d8b>] _xfs_buf_find+0x5db/0xb70
> [ 644.174012]
> [ 644.174012] other info that might help us debug this:
> [ 644.174012] Possible unsafe locking scenario:
> [ 644.174012]
> [ 644.174012] CPU0
> [ 644.174012] ----
> [ 644.174012] lock(&xfs_nondir_ilock_class);
> [ 644.174012] <Interrupt>
> [ 644.174012] lock(&xfs_nondir_ilock_class);
> [ 644.174012]
> [ 644.174012] *** DEADLOCK ***
> [ 644.174012]
> [ 644.174012] 4 locks held by fsstress/3365:
> [ 644.174012] #0: (sb_writers#10){++++++}, at: [<ffffffff81208d04>] mnt_want_write+0x24/0x50
> [ 644.174012] #1: (&sb->s_type->i_mutex_key#12){++++++}, at: [<ffffffff8120ea2f>] vfs_setxattr+0x6f/0xb0
> [ 644.174012] #2: (sb_internal#2){++++++}, at: [<ffffffff8138185c>] xfs_trans_alloc+0xfc/0x140
> [ 644.174012] #3: (&xfs_nondir_ilock_class){++++?.}, at: [<ffffffff8136f231>] xfs_ilock+0x141/0x230
> [ 644.174012]
> [ 644.174012] stack backtrace:
> [ 644.174012] CPU: 0 PID: 3365 Comm: fsstress Not tainted 4.10.0-nbor #134
> [ 644.174012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 644.174012] Call Trace:
> [ 644.174012] dump_stack+0x85/0xc9
> [ 644.174012] print_usage_bug.part.37+0x284/0x293
> [ 644.174012] ? print_shortest_lock_dependencies+0x1b0/0x1b0
> [ 644.174012] mark_lock+0x27e/0x660
> [ 644.174012] mark_held_locks+0x66/0x90
> [ 644.174012] lockdep_trace_alloc+0x6f/0xd0
> [ 644.174012] kmem_cache_alloc_node_trace+0x3a/0x2c0
> [ 644.174012] ? vm_map_ram+0x2a1/0x510
> [ 644.174012] vm_map_ram+0x2a1/0x510
> [ 644.174012] ? vm_map_ram+0x46/0x510
> [ 644.174012] _xfs_buf_map_pages+0x77/0x140
> [ 644.174012] xfs_buf_get_map+0x185/0x2a0
> [ 644.174012] xfs_attr_rmtval_set+0x233/0x430
> [ 644.174012] xfs_attr_leaf_addname+0x2d2/0x500
> [ 644.174012] xfs_attr_set+0x214/0x420
> [ 644.174012] xfs_xattr_set+0x59/0xb0
> [ 644.174012] __vfs_setxattr+0x76/0xa0
> [ 644.174012] __vfs_setxattr_noperm+0x5e/0xf0
> [ 644.174012] vfs_setxattr+0xae/0xb0
> [ 644.174012] ? __might_fault+0x43/0xa0
> [ 644.174012] setxattr+0x15e/0x1a0
> [ 644.174012] ? __lock_is_held+0x53/0x90
> [ 644.174012] ? rcu_read_lock_sched_held+0x93/0xa0
> [ 644.174012] ? rcu_sync_lockdep_assert+0x2f/0x60
> [ 644.174012] ? __sb_start_write+0x130/0x1d0
> [ 644.174012] ? mnt_want_write+0x24/0x50
> [ 644.174012] path_setxattr+0x8f/0xc0
> [ 644.174012] SyS_lsetxattr+0x11/0x20
> [ 644.174012] entry_SYSCALL_64_fastpath+0x23/0xc6
Got a similar splat during generic/048:
[ 498.776968] =================================
[ 498.777372] [ INFO: inconsistent lock state ]
[ 498.777372] 4.10.0-nbor #134 Not tainted
[ 498.777372] ---------------------------------
[ 498.777372] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
[ 498.777372] kswapd0/45 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 498.777372] (&xfs_nondir_ilock_class){++++?.}, at: [<ffffffff8136f231>] xfs_ilock+0x141/0x230
[ 498.777372] {RECLAIM_FS-ON-W} state was registered at:
[ 498.777372] mark_held_locks+0x66/0x90
[ 498.777372] lockdep_trace_alloc+0x6f/0xd0
[ 498.777372] kmem_cache_alloc_node_trace+0x3a/0x2c0
[ 498.777372] vm_map_ram+0x2a1/0x510
[ 498.777372] _xfs_buf_map_pages+0x77/0x140
[ 498.777372] xfs_buf_get_map+0x185/0x2a0
[ 498.777372] xfs_attr_rmtval_set+0x233/0x430
[ 498.777372] xfs_attr_node_addname+0x5ca/0x610
[ 498.777372] xfs_attr_set+0x3a7/0x420
[ 498.777372] xfs_xattr_set+0x59/0xb0
[ 498.777372] __vfs_setxattr+0x76/0xa0
[ 498.777372] __vfs_setxattr_noperm+0x5e/0xf0
[ 498.777372] vfs_setxattr+0xae/0xb0
[ 498.777372] setxattr+0x15e/0x1a0
[ 498.777372] path_setxattr+0x8f/0xc0
[ 498.777372] SyS_lsetxattr+0x11/0x20
[ 498.777372] entry_SYSCALL_64_fastpath+0x23/0xc6
[ 498.777372] irq event stamp: 41
[ 498.777372] hardirqs last enabled at (41): [<ffffffff8174edff>] _raw_spin_unlock_irqrestore+0x3f/0x70
[ 498.777372] hardirqs last disabled at (40): [<ffffffff8174e6be>] _raw_spin_lock_irqsave+0x2e/0x70
[ 498.777372] softirqs last enabled at (0): [<ffffffff81052121>] copy_process.part.57+0x511/0x1e10
[ 498.777372] softirqs last disabled at (0): [< (null)>] (null)
[ 498.789313]
[ 498.789313] other info that might help us debug this:
[ 498.789313] Possible unsafe locking scenario:
[ 498.789313]
[ 498.789313] CPU0
[ 498.789313] ----
[ 498.789313] lock(&xfs_nondir_ilock_class);
[ 498.789313] <Interrupt>
[ 498.789313] lock(&xfs_nondir_ilock_class);
[ 498.789313]
[ 498.789313] *** DEADLOCK ***
[ 498.789313]
[ 498.789313] 3 locks held by kswapd0/45:
[ 498.789313] #0: (shrinker_rwsem){++++..}, at: [<ffffffff81177def>] shrink_slab+0x8f/0x5f0
[ 498.789313] #1: (&type->s_umount_key#31){++++++}, at: [<ffffffff811e6f74>] trylock_super+0x24/0x60
[ 498.789313] #2: (&pag->pag_ici_reclaim_lock){+.+...}, at: [<ffffffff81364166>] xfs_reclaim_inodes_ag+0xb6/0x4e0
[ 498.789313]
[ 498.789313] stack backtrace:
[ 498.789313] CPU: 3 PID: 45 Comm: kswapd0 Not tainted 4.10.0-nbor #134
[ 498.789313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 498.789313] Call Trace:
[ 498.789313] dump_stack+0x85/0xc9
[ 498.789313] print_usage_bug.part.37+0x284/0x293
[ 498.803341] ? check_usage_backwards+0x130/0x130
[ 498.803341] mark_lock+0x27e/0x660
[ 498.803341] __lock_acquire+0x62a/0x17c0
[ 498.803341] ? add_lock_to_list.isra.19.constprop.38+0x99/0x100
[ 498.803341] ? __lock_acquire+0x1246/0x17c0
[ 498.803341] ? __lock_acquire+0x300/0x17c0
[ 498.803341] lock_acquire+0xc5/0x220
[ 498.803341] ? xfs_ilock+0x141/0x230
[ 498.803341] ? xfs_reclaim_inode+0x12a/0x320
[ 498.803341] down_write_nested+0x4f/0x90
[ 498.803341] ? xfs_ilock+0x141/0x230
[ 498.803341] xfs_ilock+0x141/0x230
[ 498.803341] xfs_reclaim_inode+0x12a/0x320
[ 498.803341] xfs_reclaim_inodes_ag+0x2c8/0x4e0
[ 498.803341] ? xfs_reclaim_inodes_ag+0xe1/0x4e0
[ 498.803341] ? mark_held_locks+0x66/0x90
[ 498.803341] ? _raw_spin_unlock_irqrestore+0x3f/0x70
[ 498.803341] ? trace_hardirqs_on_caller+0x111/0x1e0
[ 498.803341] ? trace_hardirqs_on+0xd/0x10
[ 498.803341] ? try_to_wake_up+0xf5/0x5d0
[ 498.803341] ? wake_up_process+0x15/0x20
[ 498.803341] ? xfs_ail_push+0x4e/0x60
[ 498.803341] xfs_reclaim_inodes_nr+0x33/0x40
[ 498.803341] xfs_fs_free_cached_objects+0x19/0x20
[ 498.803341] super_cache_scan+0x191/0x1a0
[ 498.803341] shrink_slab+0x26f/0x5f0
[ 498.803341] shrink_node+0xf9/0x2f0
[ 498.803341] kswapd+0x356/0x920
[ 498.803341] kthread+0x10c/0x140
[ 498.803341] ? mem_cgroup_shrink_node+0x2f0/0x2f0
[ 498.803341] ? __kthread_init_worker+0x100/0x100
[ 498.803341] ret_from_fork+0x31/0x40
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