syzbot


possible deadlock in ocfs2_xattr_set

Status: upstream: reported on 2025/06/19 18:15
Reported-by: syzbot+368e77cd4b3143bb3cba@syzkaller.appspotmail.com
First crash: 16h04m, last: 16h04m
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in ocfs2_xattr_set 302 1d21h 279d 0/3 upstream: reported on 2024/09/14 01:11
upstream possible deadlock in ocfs2_xattr_set ocfs2 2955 2h42m 283d 0/29 upstream: reported on 2024/09/10 05:07
linux-6.1 possible deadlock in ocfs2_xattr_set 298 1d04h 268d 0/3 upstream: reported on 2024/09/25 09:02

Sample crash report:
(syz.2.8410,4503,1):ocfs2_block_check_validate:402 ERROR: CRC32 failed: stored: 0xb3775c19, computed 0x2dd1c265. Applying ECC.
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.6.94-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.8410/4503 is trying to acquire lock:
ffff88805b05a658 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
ffff88805b05a658 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: ocfs2_xattr_set+0xada/0x11f0 fs/ocfs2/xattr.c:3622

but task is already holding lock:
ffff88805b191538 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_xattr_set+0x410/0x11f0 fs/ocfs2/xattr.c:3583

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&oi->ip_xattr_sem){++++}-{3:3}:
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
       ocfs2_init_acl+0x2fa/0x720 fs/ocfs2/acl.c:366
       ocfs2_mknod+0x12e5/0x20f0 fs/ocfs2/namei.c:410
       ocfs2_create+0x196/0x410 fs/ocfs2/namei.c:674
       lookup_open fs/namei.c:3488 [inline]
       open_last_lookups fs/namei.c:3556 [inline]
       path_openat+0x1277/0x3190 fs/namei.c:3786
       do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
       do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
       do_sys_open fs/open.c:1434 [inline]
       __do_sys_open fs/open.c:1442 [inline]
       __se_sys_open fs/open.c:1438 [inline]
       __x64_sys_open+0x11f/0x140 fs/open.c:1438
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (jbd2_handle){++++}-{0:0}:
       jbd2_journal_lock_updates+0xab/0x380 fs/jbd2/transaction.c:865
       __ocfs2_flush_truncate_log+0x2b8/0x10b0 fs/ocfs2/alloc.c:6030
       ocfs2_flush_truncate_log+0x4f/0x60 fs/ocfs2/alloc.c:6077
       ocfs2_sync_fs+0x117/0x310 fs/ocfs2/super.c:402
       sync_filesystem+0x1c2/0x220 fs/sync.c:66
       generic_shutdown_super+0x6f/0x2b0 fs/super.c:666
       kill_block_super+0x44/0x90 fs/super.c:1660
       deactivate_locked_super+0x97/0x100 fs/super.c:481
       cleanup_mnt+0x429/0x4c0 fs/namespace.c:1250
       task_work_run+0x1ce/0x250 kernel/task_work.c:239
       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:291 [inline]
       syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
       do_syscall_64+0x61/0xb0 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:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
       lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
       down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:804 [inline]
       ocfs2_xattr_set+0xada/0x11f0 fs/ocfs2/xattr.c:3622
       __vfs_setxattr+0x431/0x470 fs/xattr.c:201
       __vfs_setxattr_noperm+0x12d/0x5e0 fs/xattr.c:235
       vfs_setxattr+0x16c/0x2f0 fs/xattr.c:322
       do_setxattr fs/xattr.c:630 [inline]
       path_setxattr+0x362/0x550 fs/xattr.c:659
       __do_sys_setxattr fs/xattr.c:677 [inline]
       __se_sys_setxattr fs/xattr.c:673 [inline]
       __x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:673
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5 --> jbd2_handle --> &oi->ip_xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&oi->ip_xattr_sem);
                               lock(jbd2_handle);
                               lock(&oi->ip_xattr_sem);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5);

 *** DEADLOCK ***

3 locks held by syz.2.8410/4503:
 #0: ffff88807c718418 (sb_writers#28){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403
 #1: ffff88805b191818 (&type->i_mutex_dir_key#19){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #1: ffff88805b191818 (&type->i_mutex_dir_key#19){++++}-{3:3}, at: vfs_setxattr+0x145/0x2f0 fs/xattr.c:321
 #2: ffff88805b191538 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_xattr_set+0x410/0x11f0 fs/ocfs2/xattr.c:3583

stack backtrace:
CPU: 1 PID: 4503 Comm: syz.2.8410 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:804 [inline]
 ocfs2_xattr_set+0xada/0x11f0 fs/ocfs2/xattr.c:3622
 __vfs_setxattr+0x431/0x470 fs/xattr.c:201
 __vfs_setxattr_noperm+0x12d/0x5e0 fs/xattr.c:235
 vfs_setxattr+0x16c/0x2f0 fs/xattr.c:322
 do_setxattr fs/xattr.c:630 [inline]
 path_setxattr+0x362/0x550 fs/xattr.c:659
 __do_sys_setxattr fs/xattr.c:677 [inline]
 __se_sys_setxattr fs/xattr.c:673 [inline]
 __x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:673
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe55cf8e929
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:00007fe55dd4a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fe55d1b5fa0 RCX: 00007fe55cf8e929
RDX: 0000200000002700 RSI: 00002000000000c0 RDI: 0000200000000080
RBP: 00007fe55d010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001015 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe55d1b5fa0 R15: 00007ffd4ef8d978
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/19 18:14 linux-6.6.y 6282921b6825 ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in ocfs2_xattr_set
2025/06/19 18:14 linux-6.6.y 6282921b6825 ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in ocfs2_xattr_set
2025/06/19 18:14 linux-6.6.y 6282921b6825 ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in ocfs2_xattr_set
* Struck through repros no longer work on HEAD.