syzbot


possible deadlock in __ntfs_cluster_free

Status: auto-obsoleted due to no activity on 2023/04/29 12:09
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+6a2409526a801cf8c0ef@syzkaller.appspotmail.com
First crash: 517d, last: 517d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ntfs?] possible deadlock in __ntfs_cluster_free 0 (1) 2023/01/03 12:13

Sample crash report:
ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc1-syzkaller-00043-g2258c2dc850b #0 Not tainted
------------------------------------------------------
syz-executor.3/28063 is trying to acquire lock:
ffff88801e35d9f8 (&vol->lcnbmp_lock){+.+.}-{3:3}, at: __ntfs_cluster_free+0xd4/0x890 fs/ntfs/lcnalloc.c:862

but task is already holding lock:
ffff888039ccc390 (&lcnbmp_mrec_lock_key){+.+.}-{3:3}, at: map_mft_record+0x46/0x610 fs/ntfs/mft.c:154

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&lcnbmp_mrec_lock_key){+.+.}-{3:3}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       map_mft_record+0x46/0x610 fs/ntfs/mft.c:154
       __ntfs_write_inode+0x80/0xc90 fs/ntfs/inode.c:2978
       ntfs_commit_inode fs/ntfs/inode.h:300 [inline]
       ntfs_put_super+0x3ba/0xf80 fs/ntfs/super.c:2283
       generic_shutdown_super+0x130/0x310 fs/super.c:492
       kill_block_super+0x79/0xd0 fs/super.c:1386
       deactivate_locked_super+0xa7/0xf0 fs/super.c:332
       cleanup_mnt+0x494/0x520 fs/namespace.c:1291
       task_work_run+0x243/0x300 kernel/task_work.c:179
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0x124/0x150 kernel/entry/common.c:171
       exit_to_user_mode_prepare+0xb2/0x140 kernel/entry/common.c:203
       __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
       syscall_exit_to_user_mode+0x26/0x60 kernel/entry/common.c:296
       do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&vol->lcnbmp_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       down_write+0x9c/0x270 kernel/locking/rwsem.c:1562
       __ntfs_cluster_free+0xd4/0x890 fs/ntfs/lcnalloc.c:862
       ntfs_cluster_free fs/ntfs/lcnalloc.h:96 [inline]
       ntfs_truncate+0x119c/0x2720 fs/ntfs/inode.c:2695
       ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
       ntfs_setattr+0x2b9/0x3a0 fs/ntfs/inode.c:2914
       notify_change+0xe50/0x1100 fs/attr.c:482
       do_truncate+0x200/0x2f0 fs/open.c:65
       handle_truncate fs/namei.c:3216 [inline]
       do_open fs/namei.c:3561 [inline]
       path_openat+0x272b/0x2dd0 fs/namei.c:3714
       do_file_open_root+0x339/0x790 fs/namei.c:3766
       file_open_root+0x234/0x290 fs/open.c:1290
       do_handle_open+0x565/0x950 fs/fhandle.c:232
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lcnbmp_mrec_lock_key);
                               lock(&vol->lcnbmp_lock);
                               lock(&lcnbmp_mrec_lock_key);
  lock(&vol->lcnbmp_lock);

 *** DEADLOCK ***

4 locks held by syz-executor.3/28063:
 #0: ffff888038f60460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:508
 #1: ffff888039ccc670 (&sb->s_type->i_mutex_key#33){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #1: ffff888039ccc670 (&sb->s_type->i_mutex_key#33){+.+.}-{3:3}, at: do_truncate+0x1ec/0x2f0 fs/open.c:63
 #2: ffff888039ccc300 (&lcnbmp_runlist_lock_key){++++}-{3:3}, at: ntfs_truncate+0x1d8/0x2720 fs/ntfs/inode.c:2378
 #3: ffff888039ccc390 (&lcnbmp_mrec_lock_key){+.+.}-{3:3}, at: map_mft_record+0x46/0x610 fs/ntfs/mft.c:154

stack backtrace:
CPU: 0 PID: 28063 Comm: syz-executor.3 Not tainted 6.2.0-rc1-syzkaller-00043-g2258c2dc850b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 down_write+0x9c/0x270 kernel/locking/rwsem.c:1562
 __ntfs_cluster_free+0xd4/0x890 fs/ntfs/lcnalloc.c:862
 ntfs_cluster_free fs/ntfs/lcnalloc.h:96 [inline]
 ntfs_truncate+0x119c/0x2720 fs/ntfs/inode.c:2695
 ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
 ntfs_setattr+0x2b9/0x3a0 fs/ntfs/inode.c:2914
 notify_change+0xe50/0x1100 fs/attr.c:482
 do_truncate+0x200/0x2f0 fs/open.c:65
 handle_truncate fs/namei.c:3216 [inline]
 do_open fs/namei.c:3561 [inline]
 path_openat+0x272b/0x2dd0 fs/namei.c:3714
 do_file_open_root+0x339/0x790 fs/namei.c:3766
 file_open_root+0x234/0x290 fs/open.c:1290
 do_handle_open+0x565/0x950 fs/fhandle.c:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f169e08c0a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f169ee1f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007f169e1abf80 RCX: 00007f169e08c0a9
RDX: 0000000000000202 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f169e0e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffecb030f6f R14: 00007f169ee1f300 R15: 0000000000022000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/30 12:09 upstream 2258c2dc850b 44712fbc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in __ntfs_cluster_free
* Struck through repros no longer work on HEAD.