syzbot


possible deadlock in __ocfs2_move_extents_range

Status: upstream: reported on 2025/03/14 00:08
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+783d8c425076dd97018d@syzkaller.appspotmail.com
First crash: 47d, last: 2d06h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ocfs2?] possible deadlock in __ocfs2_move_extents_range 0 (1) 2025/03/14 00:08
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in __ocfs2_move_extents_range 3 4h30m 45d 0/3 upstream: reported on 2025/03/11 15:42
linux-6.1 possible deadlock in __ocfs2_move_extents_range 5 1d20h 42d 0/3 upstream: reported on 2025/03/15 00:05

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 Not tainted
------------------------------------------------------
syz.2.468/8382 is trying to acquire lock:
ffff88804d823480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
ffff88804d823480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
ffff88804d823480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: __ocfs2_move_extents_range+0x1f2e/0x4470 fs/ocfs2/move_extents.c:860

but task is already holding lock:
ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:632 [inline]
ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: __ocfs2_move_extents_range+0x168e/0x4470 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]#5){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       down_write+0x9c/0x220 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:867 [inline]
       __ocfs2_flush_truncate_log+0x38d/0x1240 fs/ocfs2/alloc.c:6054
       ocfs2_flush_truncate_log+0x4f/0x70 fs/ocfs2/alloc.c:6084
       ocfs2_sync_fs+0x136/0x3b0 fs/ocfs2/super.c:406
       sync_filesystem+0x1ca/0x230 fs/sync.c:66
       generic_shutdown_super+0x72/0x2d0 fs/super.c:621
       kill_block_super+0x44/0x90 fs/super.c:1710
       deactivate_locked_super+0xc6/0x130 fs/super.c:473
       cleanup_mnt+0x422/0x4c0 fs/namespace.c:1435
       task_work_run+0x253/0x310 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
       do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       down_write+0x9c/0x220 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:867 [inline]
       ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
       __ocfs2_move_extents_range+0x1f2e/0x4470 fs/ocfs2/move_extents.c:860
       ocfs2_move_extents+0x3f0/0xac0 fs/ocfs2/move_extents.c:927
       ocfs2_ioctl_move_extents+0x61c/0x840 fs/ocfs2/move_extents.c:1053
       ocfs2_ioctl+0x19b/0x7f0 fs/ocfs2/ioctl.c:946
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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.2.468/8382:
 #0: ffff888028390420 (sb_writers#23){.+.+}-{0:0}, at: mnt_want_write_file+0x5e/0x200 fs/namespace.c:600
 #1: ffff88804d94ed80 (&sb->s_type->i_mutex_key#31){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff88804d94ed80 (&sb->s_type->i_mutex_key#31){+.+.}-{4:4}, at: ocfs2_move_extents+0x1c7/0xac0 fs/ocfs2/move_extents.c:905
 #2: ffff88804d94ea20 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_move_extents+0x3cd/0xac0 fs/ocfs2/move_extents.c:925
 #3: ffff88804da009c0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #3: ffff88804da009c0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#3){+.+.}-{4:4}, at: ocfs2_reserve_suballoc_bits+0x18d/0x4f30 fs/ocfs2/suballoc.c:786
 #4: ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #4: ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: ocfs2_move_extent fs/ocfs2/move_extents.c:632 [inline]
 #4: ffff88804da02640 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: __ocfs2_move_extents_range+0x168e/0x4470 fs/ocfs2/move_extents.c:860

stack backtrace:
CPU: 1 UID: 0 PID: 8382 Comm: syz.2.468 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 down_write+0x9c/0x220 kernel/locking/rwsem.c:1577
 inode_lock include/linux/fs.h:867 [inline]
 ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
 __ocfs2_move_extents_range+0x1f2e/0x4470 fs/ocfs2/move_extents.c:860
 ocfs2_move_extents+0x3f0/0xac0 fs/ocfs2/move_extents.c:927
 ocfs2_ioctl_move_extents+0x61c/0x840 fs/ocfs2/move_extents.c:1053
 ocfs2_ioctl+0x19b/0x7f0 fs/ocfs2/ioctl.c:946
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe56ed8e169
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:00007fe56fc1a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe56efb5fa0 RCX: 00007fe56ed8e169
RDX: 00002000000000c0 RSI: 0000000040406f06 RDI: 0000000000000004
RBP: 00007fe56ee10a68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe56efb5fa0 R15: 00007ffc7a561de8
 </TASK>

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/15 19:18 upstream 834a4a689699 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/04/15 19:17 upstream 834a4a689699 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/04/15 19:17 upstream 834a4a689699 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/04/07 02:22 upstream 16cd1c265776 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/03/13 00:58 upstream 0fed89a961ea 1a5d9317 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/04/16 10:40 upstream 1a1d569a75f3 a95239b1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __ocfs2_move_extents_range
2025/04/07 20:53 upstream 0af2f6be1b42 2f0c9720 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __ocfs2_move_extents_range
2025/04/07 00:29 linux-next a4cda136f021 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in __ocfs2_move_extents_range
2025/04/24 02:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/24 01:36 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/23 00:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 53a8b9bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/22 16:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 53a8b9bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/19 22:58 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/19 08:25 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/15 18:28 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/11 12:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2fe2b96c3818 12ba9c21 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/11 12:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 2fe2b96c3818 12ba9c21 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/07 21:24 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 0af2f6be1b42 a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/04/07 19:48 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 0af2f6be1b42 a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
2025/03/10 00:04 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 77c95b8c7a16 163f510d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 possible deadlock in __ocfs2_move_extents_range
* Struck through repros no longer work on HEAD.