possible deadlock in __ocfs2_move_extents_range (2)

Status: upstream: reported on 2026/07/31 06:07
Reported-by: syzbot+8337a9f0ebc3b8df8f9d@syzkaller.appspotmail.com
First crash: 14d, last: 1d02h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in __ocfs2_move_extents_range ocfs2 4 318 367d 518d 0/29 auto-obsoleted due to no activity on 2025/10/20 12:22
linux-5.15 possible deadlock in __ocfs2_move_extents_range 4 33 1d03h 520d 0/3 upstream: reported on 2025/03/11 15:42
linux-6.1 possible deadlock in __ocfs2_move_extents_range 4 126 91d 517d 0/3 auto-obsoleted due to no activity on 2026/07/23 13:04
linux-6.6 possible deadlock in __ocfs2_move_extents_range 4 122 16d 412d 0/2 upstream: reported on 2025/06/27 23:37

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.80/4749 is trying to acquire lock:
ffff888072bdc2c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff888072bdc2c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:648 [inline]
ffff888072bdc2c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x1a31/0x3450 fs/ocfs2/move_extents.c:868

but task is already holding lock:
ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x131f/0x3450 fs/ocfs2/move_extents.c:868

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}:
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       __ocfs2_flush_truncate_log+0x36a/0x1220 fs/ocfs2/alloc.c:6046
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6076
       ocfs2_sync_fs+0x119/0x330 fs/ocfs2/super.c:402
       sync_filesystem+0x1be/0x220 fs/sync.c:66
       generic_shutdown_super+0x6b/0x340 fs/super.c:474
       kill_block_super+0x7c/0xe0 fs/super.c:1470
       deactivate_locked_super+0x93/0xf0 fs/super.c:332
       cleanup_mnt+0x471/0x4f0 fs/namespace.c:1191
       task_work_run+0x1d0/0x260 kernel/task_work.c:203
       exit_task_work include/linux/task_work.h:39 [inline]
       do_exit+0x9d5/0x2570 kernel/exit.c:887
       do_group_exit+0x229/0x2e0 kernel/exit.c:1030
       get_signal+0x1259/0x1340 kernel/signal.c:2880
       arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
       exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
       irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
       exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1485
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3830 [inline]
       __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       ocfs2_move_extent fs/ocfs2/move_extents.c:648 [inline]
       __ocfs2_move_extents_range+0x1a31/0x3450 fs/ocfs2/move_extents.c:868
       ocfs2_move_extents+0x409/0xa40 fs/ocfs2/move_extents.c:940
       ocfs2_ioctl_move_extents+0x4d4/0x6e0 fs/ocfs2/move_extents.c:1066
       ocfs2_ioctl+0x31d/0x7c0 fs/ocfs2/ioctl.c:946
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6);

 *** DEADLOCK ***

5 locks held by syz.2.80/4749:
 #0: ffff888055dc8460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x5c/0x200 fs/namespace.c:446
 #1: ffff888054cfa648 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888054cfa648 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: ocfs2_move_extents+0x19d/0xa40 fs/ocfs2/move_extents.c:918
 #2: ffff888054cfa2e0 (&oi->ip_alloc_sem){++++}-{3:3}, at: ocfs2_move_extents+0x3fc/0xa40 fs/ocfs2/move_extents.c:938
 #3: ffff8880729adf48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #3: ffff8880729adf48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{3:3}, at: ocfs2_reserve_suballoc_bits+0x16a/0x4810 fs/ocfs2/suballoc.c:804
 #4: ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #4: ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
 #4: ffff8880729a89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x131f/0x3450 fs/ocfs2/move_extents.c:868

stack backtrace:
CPU: 0 PID: 4749 Comm: syz.2.80 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3830 [inline]
 __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 down_write+0x36/0x60 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 ocfs2_move_extent fs/ocfs2/move_extents.c:648 [inline]
 __ocfs2_move_extents_range+0x1a31/0x3450 fs/ocfs2/move_extents.c:868
 ocfs2_move_extents+0x409/0xa40 fs/ocfs2/move_extents.c:940
 ocfs2_ioctl_move_extents+0x4d4/0x6e0 fs/ocfs2/move_extents.c:1066
 ocfs2_ioctl+0x31d/0x7c0 fs/ocfs2/ioctl.c:946
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff14e59e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff14c7f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff14e826090 RCX: 00007ff14e59e0d9
RDX: 00002000000000c0 RSI: 0000000040406f06 RDI: 0000000000000007
RBP: 00007ff14e635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff14e826128 R14: 00007ff14e826090 R15: 00007fffe2f69c88
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/13 08:26 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
2026/08/13 08:25 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
2026/08/13 08:23 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
2026/07/31 06:16 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
2026/07/31 06:06 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
* Struck through repros no longer work on HEAD.