syzbot


INFO: task hung in reiserfs_lookup

Status: upstream: reported on 2025/05/10 20:36
Reported-by: syzbot+ecde9caa492b0354e799@syzkaller.appspotmail.com
First crash: 27d, last: 27d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in reiserfs_lookup (2) reiserfs 1 528d 528d 0/28 auto-obsoleted due to no activity on 2024/03/26 00:48
linux-5.15 INFO: task hung in reiserfs_lookup (2) 1 55d 55d 0/3 upstream: reported on 2025/04/12 14:53
upstream INFO: task hung in reiserfs_lookup reiserfs 4 687d 746d 0/28 auto-obsoleted due to no activity on 2023/10/18 16:15
linux-5.15 INFO: task hung in reiserfs_lookup 2 302d 302d 0/3 auto-obsoleted due to no activity on 2024/11/17 09:54

Sample crash report:
INFO: task syz.2.15:4466 blocked for more than 143 seconds.
      Not tainted 6.1.138-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.15        state:D stack:0     pid:4466  ppid:4301   flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6696
 __mutex_lock_common+0xad4/0x1f38 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
 reiserfs_lookup+0x11c/0x378 fs/reiserfs/namei.c:364
 lookup_one_qstr_excl+0x108/0x230 fs/namei.c:1605
 filename_create+0x1cc/0x39c fs/namei.c:3877
 do_mkdirat+0xa8/0x3e0 fs/namei.c:4121
 __do_sys_mkdirat fs/namei.c:4146 [inline]
 __se_sys_mkdirat fs/namei.c:4144 [inline]
 __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4144
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task syz.2.15:4467 blocked for more than 143 seconds.
      Not tainted 6.1.138-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.15        state:D stack:0     pid:4467  ppid:4301   flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6696
 rwsem_down_read_slowpath+0x4ac/0x788 kernel/locking/rwsem.c:1094
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0xa8/0x304 kernel/locking/rwsem.c:1522
 inode_lock_shared include/linux/fs.h:768 [inline]
 lookup_slow+0x4c/0x80 fs/namei.c:1706
 walk_component+0x270/0x364 fs/namei.c:1998
 lookup_last fs/namei.c:2455 [inline]
 path_lookupat+0x13c/0x3d0 fs/namei.c:2479
 filename_lookup+0x190/0x42c fs/namei.c:2508
 user_path_at_empty+0x5c/0x84 fs/namei.c:2905
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3397 [inline]
 __do_sys_mount fs/namespace.c:3608 [inline]
 __se_sys_mount fs/namespace.c:3585 [inline]
 __arm64_sys_mount+0x468/0x584 fs/namespace.c:3585
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
3 locks held by kworker/u4:1/11:
 #0: ffff0000d554e938 ((wq_completion)l2tp){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff80001c837c20 ((work_completion)(&tunnel->del_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff80001524c840 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x58/0x5d4 kernel/rcu/tree.c:4019
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015247630 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015247e50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
3 locks held by kworker/1:0/22:
 #0: ffff0000d5fe0d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff80001c8f7c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by khungtaskd/28:
 #0: ffff800015246cc0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4067:
 #0: ffff0000d64c4098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001ce702f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xf9c drivers/tty/n_tty.c:2198
4 locks held by kworker/1:3/4346:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020ea7c20 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff0000d54d80e0 (&type->s_umount_key#53){++++}-{3:3}, at: flush_old_commits+0xc8/0x29c fs/reiserfs/super.c:97
 #3: ffff0000d1c1f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
3 locks held by kworker/0:6/4351:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020ef7c20 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/u4:8/4389:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800021077c20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
4 locks held by kworker/u4:9/4390:
 #0: ffff0000c03dd138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800021087c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176cc890 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x12c/0xa74 net/core/net_namespace.c:594
 #3: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by kworker/u4:10/4406:
3 locks held by syz.2.15/4446:
3 locks held by syz.2.15/4466:
 #0: ffff0000d54d8460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff0000f5d90980 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff0000f5d90980 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: filename_create+0x1ac/0x39c fs/namei.c:3876
 #2: ffff0000d1c1f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
1 lock held by syz.2.15/4467:
 #0: ffff0000f5d90980 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff0000f5d90980 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: lookup_slow+0x4c/0x80 fs/namei.c:1706
3 locks held by kworker/0:16/6160:
 #0: ffff0000d5fe0d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800021857c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz-executor/6303:
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6ec/0xce4 net/core/rtnetlink.c:6150
4 locks held by udevd/6420:
1 lock held by udevd/6530:
1 lock held by syz-executor/6587:
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6ec/0xce4 net/core/rtnetlink.c:6150
1 lock held by syz.6.363/6657:
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176d8f08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6ec/0xce4 net/core/rtnetlink.c:6150
1 lock held by syz.4.364/6666:

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/10 20:36 linux-6.1.y 02b72ccb5f9d 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in reiserfs_lookup
* Struck through repros no longer work on HEAD.