syzbot


possible deadlock in ocfs2_xattr_remove

Status: upstream: reported on 2026/01/22 16:49
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+7df4afa14aeda476a7a1@syzkaller.appspotmail.com
First crash: 7d09h, last: 7d09h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ocfs2?] possible deadlock in ocfs2_xattr_remove 0 (1) 2026/01/22 16:49

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/74 is trying to acquire lock:
ffff8880474c6d80 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
ffff8880474c6d80 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_xattr_free_block fs/ocfs2/xattr.c:2555 [inline]
ffff8880474c6d80 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_xattr_remove+0x8f4/0x1530 fs/ocfs2/xattr.c:2630

but task is already holding lock:
ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_wipe_inode fs/ocfs2/inode.c:854 [inline]
ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0xf6c/0x4040 fs/ocfs2/inode.c:1299

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}:
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
       inode_lock include/linux/fs.h:1027 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:854 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
       ocfs2_evict_inode+0xf6c/0x4040 fs/ocfs2/inode.c:1299
       evict+0x5f4/0xae0 fs/inode.c:837
       ocfs2_dentry_iput+0x247/0x370 fs/ocfs2/dcache.c:407
       __dentry_kill+0x209/0x660 fs/dcache.c:670
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
       shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
       prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
       super_cache_scan+0x369/0x4b0 fs/super.c:222
       do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
       shrink_slab_memcg mm/shrinker.c:550 [inline]
       shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
       shrink_one+0x2d9/0x720 mm/vmscan.c:4921
       shrink_many mm/vmscan.c:4982 [inline]
       lru_gen_shrink_node mm/vmscan.c:5060 [inline]
       shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
       kswapd_shrink_node mm/vmscan.c:6901 [inline]
       balance_pgdat mm/vmscan.c:7084 [inline]
       kswapd+0x145a/0x2820 mm/vmscan.c:7354
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #2 (&osb->nfs_sync_rwlock){.+.+}-{4:4}:
       down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537
       ocfs2_nfs_sync_lock+0x106/0x250 fs/ocfs2/dlmglue.c:2875
       ocfs2_delete_inode fs/ocfs2/inode.c:1108 [inline]
       ocfs2_evict_inode+0x38d/0x4040 fs/ocfs2/inode.c:1299
       evict+0x5f4/0xae0 fs/inode.c:837
       ocfs2_dentry_iput+0x247/0x370 fs/ocfs2/dcache.c:407
       __dentry_kill+0x209/0x660 fs/dcache.c:670
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
       shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
       prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
       super_cache_scan+0x369/0x4b0 fs/super.c:222
       do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
       shrink_slab_memcg mm/shrinker.c:550 [inline]
       shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
       shrink_one+0x2d9/0x720 mm/vmscan.c:4921
       shrink_many mm/vmscan.c:4982 [inline]
       lru_gen_shrink_node mm/vmscan.c:5060 [inline]
       shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
       kswapd_shrink_node mm/vmscan.c:6901 [inline]
       balance_pgdat mm/vmscan.c:7084 [inline]
       kswapd+0x145a/0x2820 mm/vmscan.c:7354
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4301 [inline]
       fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315
       might_alloc include/linux/sched/mm.h:317 [inline]
       slab_pre_alloc_hook mm/slub.c:4904 [inline]
       slab_alloc_node mm/slub.c:5239 [inline]
       __kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5771
       kmalloc_noprof include/linux/slab.h:957 [inline]
       kzalloc_noprof include/linux/slab.h:1094 [inline]
       ocfs2_reserve_clusters_with_limit+0xea/0xba0 fs/ocfs2/suballoc.c:1156
       ocfs2_mknod+0xe10/0x2030 fs/ocfs2/namei.c:358
       ocfs2_create+0x195/0x420 fs/ocfs2/namei.c:677
       lookup_open fs/namei.c:4440 [inline]
       open_last_lookups fs/namei.c:4540 [inline]
       path_openat+0x18bb/0x3dd0 fs/namei.c:4784
       do_filp_open+0x1fa/0x410 fs/namei.c:4814
       do_sys_openat2+0x121/0x200 fs/open.c:1430
       do_sys_open fs/open.c:1436 [inline]
       __do_sys_open fs/open.c:1444 [inline]
       __se_sys_open fs/open.c:1440 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1440
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
       inode_lock include/linux/fs.h:1027 [inline]
       ocfs2_xattr_free_block fs/ocfs2/xattr.c:2555 [inline]
       ocfs2_xattr_remove+0x8f4/0x1530 fs/ocfs2/xattr.c:2630
       ocfs2_wipe_inode fs/ocfs2/inode.c:884 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
       ocfs2_evict_inode+0x1407/0x4040 fs/ocfs2/inode.c:1299
       evict+0x5f4/0xae0 fs/inode.c:837
       ocfs2_dentry_iput+0x247/0x370 fs/ocfs2/dcache.c:407
       __dentry_kill+0x209/0x660 fs/dcache.c:670
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
       shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
       prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
       super_cache_scan+0x369/0x4b0 fs/super.c:222
       do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
       shrink_slab_memcg mm/shrinker.c:550 [inline]
       shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
       shrink_one+0x2d9/0x720 mm/vmscan.c:4921
       shrink_many mm/vmscan.c:4982 [inline]
       lru_gen_shrink_node mm/vmscan.c:5060 [inline]
       shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
       kswapd_shrink_node mm/vmscan.c:6901 [inline]
       balance_pgdat mm/vmscan.c:7084 [inline]
       kswapd+0x145a/0x2820 mm/vmscan.c:7354
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE] --> &osb->nfs_sync_rwlock --> &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
                               lock(&osb->nfs_sync_rwlock);
                               lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
  lock(&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]);

 *** DEADLOCK ***

4 locks held by kswapd0/74:
 #0: ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline]
 #0: ffffffff8e051900 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354
 #1: ffff8880112f60e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline]
 #1: ffff8880112f60e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197
 #2: ffff888037e50bd0 (&osb->nfs_sync_rwlock){.+.+}-{4:4}, at: ocfs2_nfs_sync_lock+0x106/0x250 fs/ocfs2/dlmglue.c:2875
 #3: ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
 #3: ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_wipe_inode fs/ocfs2/inode.c:854 [inline]
 #3: ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
 #3: ffff8880474c5f40 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0xf6c/0x4040 fs/ocfs2/inode.c:1299

stack backtrace:
CPU: 0 UID: 0 PID: 74 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
 inode_lock include/linux/fs.h:1027 [inline]
 ocfs2_xattr_free_block fs/ocfs2/xattr.c:2555 [inline]
 ocfs2_xattr_remove+0x8f4/0x1530 fs/ocfs2/xattr.c:2630
 ocfs2_wipe_inode fs/ocfs2/inode.c:884 [inline]
 ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
 ocfs2_evict_inode+0x1407/0x4040 fs/ocfs2/inode.c:1299
 evict+0x5f4/0xae0 fs/inode.c:837
 ocfs2_dentry_iput+0x247/0x370 fs/ocfs2/dcache.c:407
 __dentry_kill+0x209/0x660 fs/dcache.c:670
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
 prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
 super_cache_scan+0x369/0x4b0 fs/super.c:222
 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
 shrink_slab_memcg mm/shrinker.c:550 [inline]
 shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
 shrink_one+0x2d9/0x720 mm/vmscan.c:4921
 shrink_many mm/vmscan.c:4982 [inline]
 lru_gen_shrink_node mm/vmscan.c:5060 [inline]
 shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
 kswapd_shrink_node mm/vmscan.c:6901 [inline]
 balance_pgdat mm/vmscan.c:7084 [inline]
 kswapd+0x145a/0x2820 mm/vmscan.c:7354
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/18 16:45 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_xattr_remove
* Struck through repros no longer work on HEAD.