syzbot


INFO: task hung in fuse_direct_IO (3)

Status: auto-obsoleted due to no activity on 2025/09/30 10:03
Subsystems: kernel
[Documentation on labels]
First crash: 159d, last: 159d
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in fuse_direct_IO 1 1 1387d 1387d 0/1 auto-closed as invalid on 2022/06/20 01:55
upstream INFO: task hung in fuse_direct_IO fuse 1 1 795d 795d 0/29 auto-obsoleted due to no activity on 2024/01/02 16:16
upstream INFO: task hung in fuse_direct_IO (2) fuse 1 3 420d 470d 0/29 auto-obsoleted due to no activity on 2025/01/12 09:59
upstream INFO: task hung in fuse_direct_IO (4) kernel 1 1 67d 67d 0/29 auto-obsoleted due to no activity on 2025/12/01 01:33

Sample crash report:
INFO: task syz.9.7839:21198 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc4-next-20250630-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.7839      state:D stack:25208 pid:21198 tgid:21196 ppid:13807  task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5313 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6696
 __schedule_loop kernel/sched/core.c:6774 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6789
 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
 fuse_direct_IO+0x9d6/0x1210 fs/fuse/file.c:2867
 fuse_direct_write_iter fs/fuse/file.c:1688 [inline]
 fuse_file_write_iter+0x7b6/0x10a0 fs/fuse/file.c:1737
 aio_write+0x535/0x7a0 fs/aio.c:1634
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x78b/0x1310 fs/aio.c:2053
 __do_sys_io_submit fs/aio.c:2112 [inline]
 __se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f852ff8e929
RSP: 002b:00007f8530de4038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f85301b6080 RCX: 00007f852ff8e929
RDX: 0000200000000780 RSI: 0000000000000002 RDI: 00007f8530dbb000
RBP: 00007f8530010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f85301b6080 R15: 00007ffe691c5bb8
 </TASK>
INFO: task syz.9.7839:21229 blocked for more than 144 seconds.
      Not tainted 6.16.0-rc4-next-20250630-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.7839      state:D stack:28552 pid:21229 tgid:21196 ppid:13807  task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5313 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6696
 __schedule_loop kernel/sched/core.c:6774 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6789
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6846
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:869 [inline]
 fuse_dio_lock fs/fuse/file.c:-1 [inline]
 fuse_direct_write_iter fs/fuse/file.c:1683 [inline]
 fuse_file_write_iter+0x72a/0x10a0 fs/fuse/file.c:1737
 aio_write+0x535/0x7a0 fs/aio.c:1634
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x78b/0x1310 fs/aio.c:2053
 __do_sys_io_submit fs/aio.c:2112 [inline]
 __se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f852ff8e929
RSP: 002b:00007f8530dba038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f85301b6160 RCX: 00007f852ff8e929
RDX: 0000200000000780 RSI: 0000000000000002 RDI: 00007f8530dbb000
RBP: 00007f8530010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f85301b6160 R15: 00007ffe691c5bb8
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/1:0/24:
 #0: ffff888021ae4148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #0: ffff888021ae4148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3322
 #1: ffffc900001e7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3215 [inline]
 #1: ffffc900001e7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3322
 #2: ffff888145368198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline]
 #2: ffff888145368198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5899
 #3: ffff88814536a510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3256 [inline]
 #3: ffff88814536a510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5468 [inline]
 #3: ffff88814536a510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5711 [inline]
 #3: ffff88814536a510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #3: ffff88814536a510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21a3/0x4a00 drivers/usb/core/hub.c:5953
 #4: ffff888145322a68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5469 [inline]
 #4: ffff888145322a68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5711 [inline]
 #4: ffff888145322a68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #4: ffff888145322a68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21cb/0x4a00 drivers/usb/core/hub.c:5953
1 lock held by khungtaskd/31:
 #0: ffffffff8e33bee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e33bee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e33bee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5595:
 #0: ffff88814e2260a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000331b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/1:4/5899:
 #0: ffff88801a880d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #0: ffff88801a880d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3322
 #1: ffffc90004497bc0 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3215 [inline]
 #1: ffffc90004497bc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3322
 #2: ffffffff8e3419f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #2: ffffffff8e3419f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:967
5 locks held by kworker/1:3/18482:
 #0: ffff888021ae4148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #0: ffff888021ae4148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3322
 #1: ffffc90002f47bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3215 [inline]
 #1: ffffc90002f47bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3322
 #2: ffff888146360198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline]
 #2: ffff888146360198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5899
 #3: ffff888146363510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3256 [inline]
 #3: ffff888146363510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5468 [inline]
 #3: ffff888146363510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5711 [inline]
 #3: ffff888146363510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #3: ffff888146363510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21a3/0x4a00 drivers/usb/core/hub.c:5953
 #4: ffff888145f0b468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5469 [inline]
 #4: ffff888145f0b468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5711 [inline]
 #4: ffff888145f0b468 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #4: ffff888145f0b468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21cb/0x4a00 drivers/usb/core/hub.c:5953
1 lock held by syz.9.7839/21198:
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_dio_lock fs/fuse/file.c:-1 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_direct_write_iter fs/fuse/file.c:1683 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_file_write_iter+0x72a/0x10a0 fs/fuse/file.c:1737
1 lock held by syz.9.7839/21229:
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_dio_lock fs/fuse/file.c:-1 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_direct_write_iter fs/fuse/file.c:1683 [inline]
 #0: ffff88805aceab48 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: fuse_file_write_iter+0x72a/0x10a0 fs/fuse/file.c:1737
1 lock held by syz.7.7968/22633:
3 locks held by syz.3.8031/23537:
 #0: ffff88806e8bcdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
 #0: ffff88806e8bcdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715
 #1: ffff88806e8bc0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282
 #2: ffffffff8f88ff68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2048 [inline]
 #2: ffffffff8f88ff68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2560
5 locks held by syz.0.8029/24255:
 #0: ffff88804894cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
 #0: ffff88804894cdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715
 #1: ffff88804894c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282
 #2: ffffffff8f88ff68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2048 [inline]
 #2: ffffffff8f88ff68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2560
 #3: ffff888029dedb38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 net/bluetooth/l2cap_core.c:1762
 #4: ffffffff8e3419f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #4: ffffffff8e3419f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:967
2 locks held by syz.8.8529/28686:
 #0: ffff888055d34dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
 #0: ffff888055d34dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715
 #1: ffff888055d340b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 net/bluetooth/hci_sync.c:5282
2 locks held by sed/28733:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-next-20250630-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2983 Comm: kworker/u8:6 Not tainted 6.16.0-rc4-next-20250630-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_mcast_mla_update
RIP: 0010:batadv_mcast_mla_forw_flags_get net/batman-adv/multicast.c:252 [inline]
RIP: 0010:batadv_mcast_mla_flags_get net/batman-adv/multicast.c:289 [inline]
RIP: 0010:__batadv_mcast_mla_update net/batman-adv/multicast.c:909 [inline]
RIP: 0010:batadv_mcast_mla_update+0x6d7/0x3670 net/batman-adv/multicast.c:948
Code: ff df 4c 8b 3d 5a 9a e1 0e 49 81 ff c0 2b 25 9a 0f 84 71 01 00 00 4c 8b 64 24 50 4d 8d 77 10 4c 89 f0 48 c1 e8 03 0f b6 04 08 <84> c0 0f 85 15 01 00 00 45 0f b6 36 bf 03 00 00 00 44 89 f6 e8 f0
RSP: 0000:ffffc9000bb0f8a0 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: ffffc9000bb0fa70 R08: 0000000000000000 R09: ffffffff8b438c26
R10: dffffc0000000000 R11: ffffed100fe304d0 R12: ffff888029e88d88
R13: ffff88807e01c718 R14: ffff88804a148810 R15: ffff88804a148800
FS:  0000000000000000(0000) GS:ffff888125ae4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffded5af788 CR3: 000000000e136000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 3a810b1eb6134bdc DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 process_one_work kernel/workqueue.c:3239 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3322
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3403
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/02 09:52 linux-next 1343433ed389 ffe4b334 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in fuse_direct_IO
* Struck through repros no longer work on HEAD.