syzbot


possible deadlock in ocfs2_xattr_set

Status: upstream: reported on 2024/09/14 01:11
Reported-by: syzbot+1cd2ae4e4eb3cb4218a3@syzkaller.appspotmail.com
First crash: 5d07h, last: 4d14h
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_xattr_set ocfs2 16 13h09m 9d03h 0/28 upstream: reported on 2024/09/10 05:07

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.167-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.435/6159 is trying to acquire lock:
ffff8880615e3488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff8880615e3488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_xattr_set+0xe96/0x1930 fs/ocfs2/xattr.c:3618

but task is already holding lock:
ffff8880615e4e38 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_xattr_set+0x62f/0x1930 fs/ocfs2/xattr.c:3579

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&oi->ip_xattr_sem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_init_acl+0x398/0x930 fs/ocfs2/acl.c:365
       ocfs2_mknod+0x1e8f/0x2cd0 fs/ocfs2/namei.c:408
       ocfs2_create+0x194/0x430 fs/ocfs2/namei.c:672
       lookup_open fs/namei.c:3462 [inline]
       open_last_lookups fs/namei.c:3532 [inline]
       path_openat+0x130a/0x2f20 fs/namei.c:3739
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_open fs/open.c:1277 [inline]
       __se_sys_open fs/open.c:1273 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1273
       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

-> #1 (jbd2_handle){++++}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       jbd2_journal_lock_updates+0xa1/0x370 fs/jbd2/transaction.c:881
       __ocfs2_flush_truncate_log+0x2e7/0x11c0 fs/ocfs2/alloc.c:6020
       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+0x6e/0x2c0 fs/super.c:448
       kill_block_super+0x7a/0xe0 fs/super.c:1425
       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

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{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:789 [inline]
       ocfs2_xattr_set+0xe96/0x1930 fs/ocfs2/xattr.c:3618
       __vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
       __vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
       vfs_setxattr+0x21d/0x420 fs/xattr.c:303
       do_setxattr fs/xattr.c:588 [inline]
       setxattr+0x27e/0x2e0 fs/xattr.c:611
       path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
       __do_sys_lsetxattr fs/xattr.c:653 [inline]
       __se_sys_lsetxattr fs/xattr.c:649 [inline]
       __x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:649
       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

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6 --> 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]#6);

 *** DEADLOCK ***

3 locks held by syz.4.435/6159:
 #0: ffff888023dd6460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
 #1: ffff8880615e5108 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff8880615e5108 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: vfs_setxattr+0x1dd/0x420 fs/xattr.c:302
 #2: ffff8880615e4e38 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_xattr_set+0x62f/0x1930 fs/ocfs2/xattr.c:3579

stack backtrace:
CPU: 0 PID: 6159 Comm: syz.4.435 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
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:789 [inline]
 ocfs2_xattr_set+0xe96/0x1930 fs/ocfs2/xattr.c:3618
 __vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
 __vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
 vfs_setxattr+0x21d/0x420 fs/xattr.c:303
 do_setxattr fs/xattr.c:588 [inline]
 setxattr+0x27e/0x2e0 fs/xattr.c:611
 path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
 __do_sys_lsetxattr fs/xattr.c:653 [inline]
 __se_sys_lsetxattr fs/xattr.c:649 [inline]
 __x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:649
 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
RIP: 0033:0x7f3f83f54ef9
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:00007f3f823ac038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f3f8410d058 RCX: 00007f3f83f54ef9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020000080
RBP: 00007f3f83fc7b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3f8410d058 R15: 00007ffc19d139b8
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/14 17:27 linux-5.15.y 3a5928702e71 c7e35043 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_xattr_set
2024/09/14 02:14 linux-5.15.y 3a5928702e71 b58f933c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_xattr_set
2024/09/14 01:10 linux-5.15.y 3a5928702e71 b58f933c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_xattr_set
* Struck through repros no longer work on HEAD.