syzbot


INFO: task hung in reiserfs_lookup (2)

Status: upstream: reported on 2025/04/12 14:53
Reported-by: syzbot+78585c2e6ede73033f00@syzkaller.appspotmail.com
First crash: 9d11h, last: 9d11h
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in reiserfs_lookup (2) reiserfs 1 482d 482d 0/28 auto-obsoleted due to no activity on 2024/03/26 00:48
upstream INFO: task hung in reiserfs_lookup reiserfs 4 641d 699d 0/28 auto-obsoleted due to no activity on 2023/10/18 16:15
linux-5.15 INFO: task hung in reiserfs_lookup 2 255d 255d 0/3 auto-obsoleted due to no activity on 2024/11/17 09:54

Sample crash report:
INFO: task syz.3.491:6859 blocked for more than 144 seconds.
      Not tainted 5.15.180-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.491       state:D stack:    0 pid: 6859 ppid:  4024 flags:0x04000001
Call trace:
 __switch_to+0x308/0x588 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6518
 __mutex_lock_common+0xba0/0x2154 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
 reiserfs_lookup+0x130/0x3c4 fs/reiserfs/namei.c:364
 lookup_open fs/namei.c:3440 [inline]
 open_last_lookups fs/namei.c:3532 [inline]
 path_openat+0xd9c/0x26cc fs/namei.c:3739
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3769
 do_sys_openat2+0x128/0x3e0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1280
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff800014d51b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:311
2 locks held by kworker/u4:1/136:
4 locks held by kworker/0:2/3323:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800021667c00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
 #2: ffff0000db3200e0 (&type->s_umount_key#109){.+.+}-{3:3}, at: flush_old_commits+0xcc/0x2b8 fs/reiserfs/super.c:97
 #3: ffff0000e721c090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
2 locks held by getty/3788:
 #0: ffff0000d3df8098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001d6ab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1204 drivers/tty/n_tty.c:2158
3 locks held by kworker/u5:6/4036:
 #0: ffff0000dcd89938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800020067c00 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
 #2: ffff0000f3254ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xb8/0x104c net/bluetooth/hci_core.c:1446
2 locks held by kworker/1:11/5149:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800020957c00 (key_gc_work){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
4 locks held by syz.3.491/6842:
3 locks held by syz.3.491/6859:
 #0: ffff0000db320460 (sb_writers#32){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
 #1: ffff0000f1728980 (&type->i_mutex_dir_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff0000f1728980 (&type->i_mutex_dir_key#22){+.+.}-{3:3}, at: open_last_lookups fs/namei.c:3529 [inline]
 #1: ffff0000f1728980 (&type->i_mutex_dir_key#22){+.+.}-{3:3}, at: path_openat+0x640/0x26cc fs/namei.c:3739
 #2: ffff0000e721c090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
1 lock held by syz.2.770/8411:
1 lock held by udevd/8415:
1 lock held by sed/8482:

=============================================


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/12 14:52 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in reiserfs_lookup
* Struck through repros no longer work on HEAD.