syzbot


possible deadlock in __ocfs2_move_extents_range

Status: upstream: reported on 2025/03/15 00:05
Reported-by: syzbot+afc4f58a184a4dc71d3c@syzkaller.appspotmail.com
First crash: 50d, last: 1h19m
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in __ocfs2_move_extents_range ocfs2 49 39m 51d 0/28 upstream: reported on 2025/03/14 00:08
linux-5.15 possible deadlock in __ocfs2_move_extents_range 5 8h52m 53d 0/3 upstream: reported on 2025/03/11 15:42

Sample crash report:
ocfs2: Mounting device (7,1) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.1.136-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.25/4452 is trying to acquire lock:
ffff888067616d88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff888067616d88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
ffff888067616d88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x1a61/0x3360 fs/ocfs2/move_extents.c:860

but task is already holding lock:
ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:632 [inline]
ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x136d/0x3360 fs/ocfs2/move_extents.c:860

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]#4){+.+.}-{3:3}:
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       __ocfs2_flush_truncate_log+0x34f/0x11d0 fs/ocfs2/alloc.c:6047
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6077
       ocfs2_sync_fs+0x113/0x310 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+0x463/0x4f0 fs/namespace.c:1186
       task_work_run+0x1ca/0x250 kernel/task_work.c:203
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
       __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       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:640 [inline]
       __ocfs2_move_extents_range+0x1a61/0x3360 fs/ocfs2/move_extents.c:860
       ocfs2_move_extents+0x37c/0x960 fs/ocfs2/move_extents.c:927
       ocfs2_ioctl_move_extents+0x4da/0x6b0 fs/ocfs2/move_extents.c:1053
       ocfs2_ioctl+0x2d7/0x740 fs/ocfs2/ioctl.c:930
       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:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       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]#4);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5);

 *** DEADLOCK ***

5 locks held by syz.1.25/4452:
 #0: ffff88807c49c460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x5c/0x200 fs/namespace.c:437
 #1: ffff8880742009c8 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880742009c8 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: ocfs2_move_extents+0x1a0/0x960 fs/ocfs2/move_extents.c:905
 #2: ffff888074200660 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_move_extents+0x36f/0x960 fs/ocfs2/move_extents.c:925
 #3: ffff888067613488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #3: ffff888067613488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{3:3}, at: ocfs2_reserve_suballoc_bits+0x162/0x4630 fs/ocfs2/suballoc.c:782
 #4: ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #4: ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:632 [inline]
 #4: ffff888067611808 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: __ocfs2_move_extents_range+0x136d/0x3360 fs/ocfs2/move_extents.c:860

stack backtrace:
CPU: 1 PID: 4452 Comm: syz.1.25 Not tainted 6.1.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 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:640 [inline]
 __ocfs2_move_extents_range+0x1a61/0x3360 fs/ocfs2/move_extents.c:860
 ocfs2_move_extents+0x37c/0x960 fs/ocfs2/move_extents.c:927
 ocfs2_ioctl_move_extents+0x4da/0x6b0 fs/ocfs2/move_extents.c:1053
 ocfs2_ioctl+0x2d7/0x740 fs/ocfs2/ioctl.c:930
 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:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f93f658e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f93f7457038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f93f67b5fa0 RCX: 00007f93f658e969
RDX: 00002000000000c0 RSI: 0000000040406f06 RDI: 0000000000000004
RBP: 00007f93f6610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f93f67b5fa0 R15: 00007ffe42fc6418
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/04 03:13 linux-6.1.y b6736e03756f b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __ocfs2_move_extents_range
2025/05/04 14:12 linux-6.1.y b6736e03756f b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/24 12:25 linux-6.1.y 420102835862 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/13 15:26 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/13 14:44 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/13 14:04 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
2025/03/15 00:04 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in __ocfs2_move_extents_range
* Struck through repros no longer work on HEAD.