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Message-ID: <68fb4c06.050a0220.346f24.00ba.GAE@google.com>
Date: Fri, 24 Oct 2025 02:51:02 -0700
From: syzbot <syzbot+727d161855d11d81e411@...kaller.appspotmail.com>
To: dmantipov@...dex.ru, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ocfs2?] kernel BUG in __ocfs2_move_extent

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in __ocfs2_flush_truncate_log

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/5793 is trying to acquire lock:
ffff88804461d100 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:815 [inline]
ffff88804461d100 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}, at: __ocfs2_flush_truncate_log+0x33d/0x10f0 fs/ocfs2/alloc.c:6054

but task is already holding lock:
ffff888040ccb480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:815 [inline]
ffff888040ccb480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: ocfs2_flush_truncate_log+0x47/0x70 fs/ocfs2/alloc.c:6083

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){+.+.}-{4:4}:
       lock_acquire+0x1a1/0x430 kernel/locking/lockdep.c:5825
       down_write+0x97/0x1f0 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:815 [inline]
       ocfs2_move_extent fs/ocfs2/move_extents.c:646 [inline]
       __ocfs2_move_extents_range+0x1a6a/0x3380 fs/ocfs2/move_extents.c:866
       ocfs2_move_extents+0x379/0x960 fs/ocfs2/move_extents.c:933
       ocfs2_ioctl_move_extents+0x569/0x740 fs/ocfs2/move_extents.c:1065
       ocfs2_ioctl+0x192/0x750 fs/ocfs2/ioctl.c:946
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0x100/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x188e/0x5720 kernel/locking/lockdep.c:3904
       __lock_acquire+0x138a/0x20c0 kernel/locking/lockdep.c:5202
       lock_acquire+0x1a1/0x430 kernel/locking/lockdep.c:5825
       down_write+0x97/0x1f0 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:815 [inline]
       __ocfs2_flush_truncate_log+0x33d/0x10f0 fs/ocfs2/alloc.c:6054
       ocfs2_flush_truncate_log+0x4f/0x70 fs/ocfs2/alloc.c:6084
       ocfs2_sync_fs+0x117/0x320 fs/ocfs2/super.c:402
       sync_filesystem+0x1cf/0x230 fs/sync.c:66
       generic_shutdown_super+0x6f/0x2c0 fs/super.c:621
       kill_block_super+0x44/0x90 fs/super.c:1710
       deactivate_locked_super+0xb9/0x130 fs/super.c:473
       cleanup_mnt+0x425/0x4c0 fs/namespace.c:1378
       task_work_run+0x1d5/0x260 kernel/task_work.c:239
       resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x87/0x130 kernel/entry/common.c:218
       do_syscall_64+0x103/0x210 arch/x86/entry/common.c:89
       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]#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/5793:
 #0: ffff88803ef880e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88803ef880e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88803ef880e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffff888040ccb480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:815 [inline]
 #1: ffff888040ccb480 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{4:4}, at: ocfs2_flush_truncate_log+0x47/0x70 fs/ocfs2/alloc.c:6083

stack backtrace:
CPU: 0 UID: 0 PID: 5793 Comm: syz-executor Not tainted syzkaller #0
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+0x18a/0x250 lib/dump_stack.c:120
 print_circular_bug+0x13b/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x2b5/0x3b0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x188e/0x5720 kernel/locking/lockdep.c:3904
 __lock_acquire+0x138a/0x20c0 kernel/locking/lockdep.c:5202
 lock_acquire+0x1a1/0x430 kernel/locking/lockdep.c:5825
 down_write+0x97/0x1f0 kernel/locking/rwsem.c:1577
 inode_lock include/linux/fs.h:815 [inline]
 __ocfs2_flush_truncate_log+0x33d/0x10f0 fs/ocfs2/alloc.c:6054
 ocfs2_flush_truncate_log+0x4f/0x70 fs/ocfs2/alloc.c:6084
 ocfs2_sync_fs+0x117/0x320 fs/ocfs2/super.c:402
 sync_filesystem+0x1cf/0x230 fs/sync.c:66
 generic_shutdown_super+0x6f/0x2c0 fs/super.c:621
 kill_block_super+0x44/0x90 fs/super.c:1710
 deactivate_locked_super+0xb9/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1378
 task_work_run+0x1d5/0x260 kernel/task_work.c:239
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x87/0x130 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd40db901f7
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:00007ffd33164b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fd40dc11d7d RCX: 00007fd40db901f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd33164bc0
RBP: 00007ffd33164bc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd33165c50
R13: 00007fd40dc11d7d R14: 000000000002060d R15: 00007ffd33165c90
 </TASK>
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)
(syz-executor,5793,0):ocfs2_inode_is_valid_to_delete:872 ERROR: Skipping delete of system file 72
ocfs2: Unmounting device (7,0) on (node local)


Tested on:

commit:         4fc43deb Linux 6.12.55
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git linux-6.12.y
console output: https://syzkaller.appspot.com/x/log.txt?x=126ddb04580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fe7b438dcda9b036
dashboard link: https://syzkaller.appspot.com/bug?extid=727d161855d11d81e411
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=177c7734580000

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