syzbot


possible deadlock in iterate_dir (2)

Status: upstream: reported on 2024/03/30 13:55
Reported-by: syzbot+e1f54d3599ee4841393a@syzkaller.appspotmail.com
First crash: 86d, last: 61d
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in iterate_dir (3) origin:upstream C 6 27d 82d 0/3 upstream: reported C repro on 2024/04/03 07:56
linux-6.1 possible deadlock in iterate_dir 2 341d 346d 0/3 auto-obsoleted due to no activity on 2023/10/27 20:39
linux-4.14 possible deadlock in iterate_dir ubifs C 11375 475d 1470d 0/1 upstream: reported C repro on 2020/06/15 06:16
linux-5.15 possible deadlock in iterate_dir (2) 2 208d 301d 0/3 auto-obsoleted due to no activity on 2024/03/08 13:21
linux-4.19 possible deadlock in iterate_dir 1 1642d 1642d 0/1 auto-closed as invalid on 2020/04/24 15:06
upstream possible deadlock in iterate_dir reiserfs 23 306d 548d 0/27 auto-obsoleted due to no activity on 2023/12/01 22:38
linux-5.15 possible deadlock in iterate_dir 1 455d 455d 0/3 auto-obsoleted due to no activity on 2023/07/25 13:55

Sample crash report:
REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.1.87-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/5017 is trying to acquire lock:
ffff888057162090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888079d94460 (sb_writers#13){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2595 [inline]
ffff888079d94460 (sb_writers#13){.+.+}-{0:0}, at: iterate_dir+0x484/0x560 fs/readdir.c:70

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#13){.+.+}-{0:0}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1891 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1966
       mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
       reiserfs_ioctl+0x170/0x340 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&sbi->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
       reiserfs_dirty_inode+0xee/0x240 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x331/0xf80 fs/fs-writeback.c:2433
       generic_update_time fs/inode.c:1903 [inline]
       inode_update_time fs/inode.c:1916 [inline]
       touch_atime+0x3fa/0x680 fs/inode.c:1988
       file_accessed include/linux/fs.h:2595 [inline]
       iterate_dir+0x484/0x560 fs/readdir.c:70
       __do_sys_getdents64 fs/readdir.c:369 [inline]
       __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#13);
                               lock(&sbi->lock);
                               lock(sb_writers#13);
  lock(&sbi->lock);

 *** DEADLOCK ***

3 locks held by syz-executor.2/5017:
 #0: ffff88807c59afe8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ba/0x360 fs/file.c:1062
 #1: ffff888058160980 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: iterate_dir+0x10a/0x560 fs/readdir.c:55
 #2: ffff888079d94460 (sb_writers#13){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2595 [inline]
 #2: ffff888079d94460 (sb_writers#13){.+.+}-{0:0}, at: iterate_dir+0x484/0x560 fs/readdir.c:70

stack backtrace:
CPU: 0 PID: 5017 Comm: syz-executor.2 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
 reiserfs_dirty_inode+0xee/0x240 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x331/0xf80 fs/fs-writeback.c:2433
 generic_update_time fs/inode.c:1903 [inline]
 inode_update_time fs/inode.c:1916 [inline]
 touch_atime+0x3fa/0x680 fs/inode.c:1988
 file_accessed include/linux/fs.h:2595 [inline]
 iterate_dir+0x484/0x560 fs/readdir.c:70
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f467cc7dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f467d9ee0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f467cdabf80 RCX: 00007f467cc7dea9
RDX: 0000000000000018 RSI: 00000000200003c0 RDI: 0000000000000004
RBP: 00007f467ccca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f467cdabf80 R15: 00007fff6aa9e4f8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/24 17:41 linux-6.1.y 6741e066ec76 8bdc0f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in iterate_dir
2024/03/30 13:55 linux-6.1.y e5cd595e23c1 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in iterate_dir
* Struck through repros no longer work on HEAD.