syzbot


possible deadlock in __ocfs2_flush_truncate_log

Status: upstream: reported on 2025/03/14 17:58
Reported-by: syzbot+e886c043a0ce74c263b0@syzkaller.appspotmail.com
First crash: 3d15h, last: 3d14h
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in __ocfs2_flush_truncate_log ocfs2 C 16 3d07h 2d21h 0/28 upstream: reported C repro on 2025/03/15 11:28
linux-6.1 possible deadlock in __ocfs2_flush_truncate_log 8 3d10h 3d20h 0/3 upstream: reported on 2025/03/14 12:11

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.179-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/4168 is trying to acquire lock:
ffff88805fc35108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff88805fc35108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: __ocfs2_flush_truncate_log+0x36e/0x11c0 fs/ocfs2/alloc.c:6037

but task is already holding lock:
ffff88805fc2b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff88805fc2b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_flush_truncate_log+0x43/0x60 fs/ocfs2/alloc.c:6066

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]#6){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:787 [inline]
       ocfs2_move_extent fs/ocfs2/move_extents.c:640 [inline]
       __ocfs2_move_extents_range+0x1ecb/0x43f0 fs/ocfs2/move_extents.c:860
       ocfs2_move_extents+0x3ea/0xaa0 fs/ocfs2/move_extents.c:927
       ocfs2_ioctl_move_extents+0x5d2/0x800 fs/ocfs2/move_extents.c:1053
       ocfs2_ioctl+0x2eb/0x7d0 fs/ocfs2/ioctl.c:931
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:787 [inline]
       __ocfs2_flush_truncate_log+0x36e/0x11c0 fs/ocfs2/alloc.c:6037
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6067
       ocfs2_sync_fs+0x121/0x380 fs/ocfs2/super.c:403
       sync_filesystem+0x1bc/0x220 fs/sync.c:66
       generic_shutdown_super+0x6b/0x310 fs/super.c:448
       kill_block_super+0x7a/0xe0 fs/super.c:1427
       deactivate_locked_super+0xa0/0x110 fs/super.c:335
       cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
       task_work_run+0x129/0x1a0 kernel/task_work.c:188
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
       do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by syz-executor/4168:
 #0: ffff888074f8e0e0 (&type->s_umount_key#64){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: ffff88805fc2b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805fc2b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_flush_truncate_log+0x43/0x60 fs/ocfs2/alloc.c:6066

stack backtrace:
CPU: 0 PID: 4168 Comm: syz-executor Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 inode_lock include/linux/fs.h:787 [inline]
 __ocfs2_flush_truncate_log+0x36e/0x11c0 fs/ocfs2/alloc.c:6037
 ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6067
 ocfs2_sync_fs+0x121/0x380 fs/ocfs2/super.c:403
 sync_filesystem+0x1bc/0x220 fs/sync.c:66
 generic_shutdown_super+0x6b/0x310 fs/super.c:448
 kill_block_super+0x7a/0xe0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc654f39497
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeb145f838 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc654fb908c RCX: 00007fc654f39497
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeb145f8f0
RBP: 00007ffeb145f8f0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffeb1460980
R13: 00007fc654fb908c R14: 0000000000012a5e R15: 00007ffeb14609c0
 </TASK>
ocfs2: Unmounting device (7,2) on (node local)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/14 18:09 linux-5.15.y 0c935c049b5c e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __ocfs2_flush_truncate_log
2025/03/14 17:57 linux-5.15.y 0c935c049b5c e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __ocfs2_flush_truncate_log
* Struck through repros no longer work on HEAD.