syzbot


INFO: task hung in lookup_slow

Status: upstream: reported on 2024/04/14 05:59
Reported-by: syzbot+0e98e04ea2a9550a2596@syzkaller.appspotmail.com
First crash: 65d, last: 12d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in lookup_slow (2) fs 2 1757d 1769d 0/27 auto-closed as invalid on 2019/11/26 02:54
upstream INFO: task hung in lookup_slow exfat 148 1978d 2271d 0/27 closed as dup on 2018/09/08 15:36
linux-5.15 INFO: task hung in lookup_slow (2) 18 17d 65d 0/3 upstream: reported on 2024/04/15 04:02
upstream INFO: task hung in lookup_slow (3) fs C unreliable 844 4h09m 586d 0/27 upstream: reported C repro on 2022/11/11 00:21
android-49 INFO: task hung in lookup_slow syz 36 1783d 1892d 0/3 public: reported syz repro on 2019/04/14 08:51
linux-4.14 INFO: task hung in lookup_slow C error 1 655d 685d 0/1 upstream: reported C repro on 2022/08/03 08:46
linux-4.19 INFO: task hung in lookup_slow 1 1465d 1465d 0/1 auto-closed as invalid on 2020/10/13 00:17
linux-5.15 INFO: task hung in lookup_slow 2 429d 434d 0/3 auto-obsoleted due to no activity on 2023/08/15 05:05

Sample crash report:
INFO: task syz-executor.1:11136 blocked for more than 143 seconds.
      Not tainted 6.1.92-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:25080 pid:11136 ppid:7009   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1094 [inline]
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x6ff/0xa30 kernel/locking/rwsem.c:1522
 inode_lock_shared include/linux/fs.h:768 [inline]
 lookup_slow+0x45/0x70 fs/namei.c:1706
 walk_component+0x2d0/0x400 fs/namei.c:1998
 lookup_last fs/namei.c:2455 [inline]
 path_lookupat+0x16f/0x450 fs/namei.c:2479
 filename_lookup+0x251/0x600 fs/namei.c:2508
 user_path_at_empty+0x3e/0x60 fs/namei.c:2907
 user_path_at include/linux/namei.h:57 [inline]
 __do_sys_chdir fs/open.c:514 [inline]
 __se_sys_chdir+0xbb/0x220 fs/open.c:508
 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: 0033:0x7f3c6167cf69
RSP: 002b:00007f3c6232f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000050
RAX: ffffffffffffffda RBX: 00007f3c617b4050 RCX: 00007f3c6167cf69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040
RBP: 00007f3c616da6fe R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f3c617b4050 R15: 00007ffd54d06108
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d12ae50 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d12b650 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/27:
 #0: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
2 locks held by getty/3315:
 #0: ffff888028a9c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2188
6 locks held by syz-fuzzer/3544:
2 locks held by kworker/0:6/3616:
 #0: ffff888012472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000470fd20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
5 locks held by kworker/1:15/4384:
 #0: ffff888143ac5d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000317fd20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffff888022d1e190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
 #2: ffff888022d1e190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1fe/0x5730 drivers/usb/core/hub.c:5801
 #3: ffff888022d894f8 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3159 [inline]
 #3: ffff888022d894f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5373 [inline]
 #3: ffff888022d894f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5617 [inline]
 #3: ffff888022d894f8 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5773 [inline]
 #3: ffff888022d894f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x2471/0x5730 drivers/usb/core/hub.c:5855
 #4: ffff8880204a2468 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5374 [inline]
 #4: ffff8880204a2468 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5617 [inline]
 #4: ffff8880204a2468 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5773 [inline]
 #4: ffff8880204a2468 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x249e/0x5730 drivers/usb/core/hub.c:5855
4 locks held by syz-executor.4/7177:
 #0: ffff888073dfd0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline]
 #0: ffff888073dfd0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1cf/0x4d0 net/bluetooth/hci_core.c:2736
 #1: ffff888073dfc078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x48d/0x1020 net/bluetooth/hci_sync.c:5005
 #2: ffffffff8e3f2028 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1805 [inline]
 #2: ffffffff8e3f2028 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x2a0 net/bluetooth/hci_conn.c:2441
 #3: ffffffff8d130278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #3: ffffffff8d130278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x930 kernel/rcu/tree_exp.h:962
3 locks held by kworker/0:26/8470:
 #0: ffff888012470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000a757d20 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffffffff8d130278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #2: ffffffff8d130278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x930 kernel/rcu/tree_exp.h:962
1 lock held by syz-executor.1/11136:
 #0: ffff88804a868188 (&type->i_mutex_dir_key#23){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff88804a868188 (&type->i_mutex_dir_key#23){++++}-{3:3}, at: lookup_slow+0x45/0x70 fs/namei.c:1706
2 locks held by syz-executor.1/11140:
3 locks held by syz-executor.1/13924:
 #0: ffff8880596790b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline]
 #0: ffff8880596790b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1cf/0x4d0 net/bluetooth/hci_core.c:2736
 #1: ffff888059678078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x48d/0x1020 net/bluetooth/hci_sync.c:5005
 #2: ffffffff8e3f2028 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1805 [inline]
 #2: ffffffff8e3f2028 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x2a0 net/bluetooth/hci_conn.c:2441
2 locks held by syz-executor.3/13983:
 #0: ffff88807b5310b8 (&hd

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/07 01:14 linux-6.1.y 88690811da69 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in lookup_slow
2024/04/28 20:57 linux-6.1.y f2295faba5e8 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in lookup_slow
2024/04/22 03:35 linux-6.1.y 6741e066ec76 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in lookup_slow
2024/05/14 15:18 linux-6.1.y 909ba1f1b414 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in lookup_slow
2024/04/17 01:32 linux-6.1.y cd5d98c0556c 18f6e127 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in lookup_slow
2024/04/14 06:04 linux-6.1.y cd5d98c0556c c8349e48 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in lookup_slow
2024/04/14 05:58 linux-6.1.y cd5d98c0556c c8349e48 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in lookup_slow
* Struck through repros no longer work on HEAD.