INFO: task hung in devtmpfs_create_node

Status: premoderation: reported on 2026/10/12 10:29
Reported-by: syzbot+632eacafc2150e4a70ba@syzkaller.appspotmail.com
First crash: 1d03h, last: 1d03h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in devtmpfs_create_node (3) kernel 1 4 536d 541d 0/29 auto-obsoleted due to no activity on 2025/07/24 09:38
upstream INFO: task hung in devtmpfs_create_node kernel 1 1 2527d 2527d 0/29 auto-closed as invalid on 2020/02/09 23:37
upstream INFO: task hung in devtmpfs_create_node (2) kernel 1 2 664d 707d 0/29 auto-obsoleted due to no activity on 2025/03/17 18:36

Sample crash report:
INFO: task kworker/1:0:31 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:0     pid:31    tgid:31    ppid:2      flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x16fe/0x23d0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x368/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 devtmpfs_submit_req drivers/base/devtmpfs.c:107 [inline]
 devtmpfs_create_node+0x1df/0x260 drivers/base/devtmpfs.c:138
 device_add+0xa4d/0xbf0 drivers/base/core.c:3666
 usb_new_device+0x98d/0x1500 drivers/usb/core/hub.c:2703
 hub_port_connect drivers/usb/core/hub.c:5574 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5714 [inline]
 port_event drivers/usb/core/hub.c:5878 [inline]
 hub_event+0x2dbd/0x4360 drivers/usb/core/hub.c:5960
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task khugepaged:41 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khugepaged      state:D stack:0     pid:41    tgid:41    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x16fe/0x23d0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x368/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 __flush_work+0x6a8/0xaa0 kernel/workqueue.c:4290
 flush_work+0x1b/0x40 kernel/workqueue.c:4312
 __lru_add_drain_all+0x51c/0x580 mm/swap.c:923
 lru_add_drain_all+0x14/0x30 mm/swap.c:931
 khugepaged_do_scan mm/khugepaged.c:2531 [inline]
 khugepaged+0x18a/0x1930 mm/khugepaged.c:2600
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task syz.6.497:2152 blocked for more than 125 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.497       state:D stack:0     pid:2152  tgid:2151  ppid:1586   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x16fe/0x23d0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 rwsem_down_write_slowpath+0x5c9/0x1b60 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x163/0x2b0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 fuse_dio_lock fs/fuse/file.c:-1 [inline]
 fuse_direct_write_iter fs/fuse/file.c:1785 [inline]
 fuse_file_write_iter+0xc36/0x2820 fs/fuse/file.c:1868
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x75f/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f19ec39e1d9
RSP: 002b:00007f19ed299028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f19ec625fa0 RCX: 00007f19ec39e1d9
RDX: 000000000000000d RSI: 0000200000000780 RDI: 0000000000000009
RBP: 00007f19ec435888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19ec626038 R14: 00007f19ec625fa0 R15: 00007fffdc6b2a58
 </TASK>
INFO: task syz.6.497:2153 blocked for more than 127 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.497       state:D stack:0     pid:2153  tgid:2151  ppid:1586   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x16fe/0x23d0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x368/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 fuse_direct_IO+0x940/0x11d0 fs/fuse/file.c:3271
 fuse_direct_write_iter fs/fuse/file.c:1790 [inline]
 fuse_file_write_iter+0xe84/0x2820 fs/fuse/file.c:1868
 aio_write+0x4e2/0x720 fs/aio.c:1633
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0xc74/0x19e0 fs/aio.c:2052
 __do_sys_io_submit fs/aio.c:2111 [inline]
 __se_sys_io_submit+0x17f/0x3f0 fs/aio.c:2081
 __x64_sys_io_submit+0x7f/0xa0 fs/aio.c:2081
 x64_sys_call+0x1c95/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:210
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f19ec39e1d9
RSP: 002b:00007f19ed276028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f19ec626090 RCX: 00007f19ec39e1d9
RDX: 0000200000006dc0 RSI: 0000000000000001 RDI: 00007f19ed24d000
RBP: 00007f19ec435888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19ec626128 R14: 00007f19ec626090 R15: 00007fffdc6b2a58
 </TASK>
INFO: task syz.6.497:2154 blocked for more than 129 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.497       state:D stack:0     pid:2154  tgid:2151  ppid:1586   flags:0x00000006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x16fe/0x23d0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 rwsem_down_write_slowpath+0x5c9/0x1b60 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x163/0x2b0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 fuse_flush+0x766/0x1f20 fs/fuse/file.c:580
 filp_flush fs/open.c:1546 [inline]
 filp_close+0xbd/0x160 fs/open.c:1559
 __range_close fs/file.c:726 [inline]
 __close_range+0x344/0x4e0 fs/file.c:796
 __do_sys_close_range fs/open.c:1612 [inline]
 __se_sys_close_range fs/open.c:1609 [inline]
 __x64_sys_close_range+0x7e/0x90 fs/open.c:1609
 x64_sys_call+0x1686/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:437
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f19ec39e1d9
RSP: 002b:00007f19ed24c028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007f19ec626180 RCX: 00007f19ec39e1d9
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005
RBP: 00007f19ec435888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19ec626218 R14: 00007f19ec626180 R15: 00007fffdc6b2a58
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 9109b4058d136ef0ac9398910d6f8e272823abe4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:114
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:63
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 cpumask_backtrace+0x1f/0x30 lib/nmi_backtrace.c:127
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2189 Comm: syz.3.504 Not tainted syzkaller #0 9109b4058d136ef0ac9398910d6f8e272823abe4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:49 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x70 kernel/kcov.c:216
Code: c3 cc cc cc cc cc cc cc cc cc cc cc cc cc b8 cf 8d 7a af 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 48 8b 45 08 <65> 48 8b 0d ec a1 7b 7e 65 8b 15 ed a1 7b 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc9000e5d7ad8 EFLAGS: 00000297
RAX: ffffffff81f64f70 RBX: ffff88811e350330 RCX: 0000000000000000
RDX: ffff888117be2780 RSI: 000000000000000e RDI: 0000000000000040
RBP: ffffc9000e5d7ad8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001cbaf9c R12: 000000000000000e
R13: ffff88812ccd01c0 R14: ffff88812ccd1a60 R15: 07fffc44092c0875
FS:  00007f33fc9946c0(0000) GS:ffff8881f6c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4b981ca000 CR3: 00000001328fc000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 m_hash fs/namespace.c:237 [inline]
 __lookup_mnt+0x50/0x160 fs/namespace.c:811
 propagate_umount+0x5a8/0x1660 fs/pnode.c:597
 umount_tree+0x60e/0xfa0 fs/namespace.c:1796
 do_umount fs/namespace.c:-1 [inline]
 path_umount+0xebe/0xf60 fs/namespace.c:2030
 ksys_umount fs/namespace.c:2053 [inline]
 __do_sys_umount fs/namespace.c:2058 [inline]
 __se_sys_umount fs/namespace.c:2056 [inline]
 __x64_sys_umount+0x12e/0x180 fs/namespace.c:2056
 x64_sys_call+0x2ab8/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:167
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f33fdf9e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f33fc994028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f33fe226270 RCX: 00007f33fdf9e1d9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00002000000002c0
RBP: 00007f33fe035888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f33fe226308 R14: 00007f33fe226270 R15: 00007ffd5abec178
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/12 10:28 android16-6.12 c82b35cb007f 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in devtmpfs_create_node
* Struck through repros no longer work on HEAD.