INFO: task hung in uhid_char_release

Status: premoderation: reported C repro on 2025/06/19 10:50
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+69c758044c075ca3cc58@syzkaller.appspotmail.com
First crash: 414d, last: 3d17h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/06/20 lts (merge base) 83b4161a63b8 C [report] INFO: task hung in uevent_show
2025/06/20 upstream (ToT) 75f5f23f8787 C [report] INFO: task hung in uhid_char_release
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: task hung in uhid_char_release origin:lts-only 1 syz, C error 13 68d 332d 0/2 upstream: reported C repro on 2025/09/09 09:36
upstream INFO: task hung in uhid_char_release input 1 syz, C done done 479 356d 1141d 0/29 upstream: reported C repro on 2023/06/24 03:16
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/06/19 14:32 12m retest repro android16-6.12 error
2026/06/19 14:32 13m retest repro android16-6.12 error
2026/06/19 14:32 10m retest repro android16-6.12 error
2026/05/30 17:42 18m retest repro android16-6.12 log
2026/05/30 17:42 18m retest repro android16-6.12 log
2026/05/30 17:42 20m retest repro android16-6.12 log
2026/05/30 17:42 16m retest repro android16-6.12 log
2026/05/30 17:42 16m retest repro android16-6.12 log
2026/04/10 05:05 22m retest repro android16-6.12 report log
2026/03/20 12:00 10m retest repro android16-6.12 report log

Sample crash report:
INFO: task syz-executor340:318 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor340 state:D
 stack:0     pid:318   tgid:318   ppid:314    flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 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
 __cancel_work_sync kernel/workqueue.c:4411 [inline]
 cancel_work_sync+0xac/0xe0 kernel/workqueue.c:4448
 uhid_dev_destroy drivers/hid/uhid.c:584 [inline]
 uhid_char_release+0xa7/0x600 drivers/hid/uhid.c:662
 __fput+0x208/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e8/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:955
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
 __do_sys_exit_group kernel/exit.c:1109 [inline]
 __se_sys_exit_group kernel/exit.c:1107 [inline]
 __x64_sys_exit_group+0x43/0x50 kernel/exit.c:1107
 x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7f57c3b5c945
RSP: 002b:00007ffdda41e408 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f57c3b5c945
RDX: 00000000000000e7 RSI: ffffffffffffffd0 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffdda41e4a0
R10: 00007ffdda41e4a0 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f57c3c0c128 R14: 00007f57c3c0e568 R15: 00007f57c3c0e580
 </TASK>
INFO: task syz-executor340:319 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor340 state:D
 stack:0     pid:319   tgid:319   ppid:313    flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 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
 __cancel_work_sync kernel/workqueue.c:4411 [inline]
 cancel_work_sync+0xac/0xe0 kernel/workqueue.c:4448
 uhid_dev_destroy drivers/hid/uhid.c:584 [inline]
 uhid_char_release+0xa7/0x600 drivers/hid/uhid.c:662
 __fput+0x208/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e8/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:955
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
 __do_sys_exit_group kernel/exit.c:1109 [inline]
 __se_sys_exit_group kernel/exit.c:1107 [inline]
 __x64_sys_exit_group+0x43/0x50 kernel/exit.c:1107
 x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7f57c3b5c945
RSP: 002b:00007ffdda41e408 EFLAGS: 00000202
 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f57c3b5c945
RDX: 00000000000000e7 RSI: ffffffffffffffd0 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffdda41e4a0
R10: 00007ffdda41e4a0 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f57c3c0c128 R14: 00007f57c3c0e568 R15: 00007f57c3c0e580
 </TASK>
INFO: task syz-executor340:331 blocked for more than 126 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor340 state:D
 stack:0     pid:331   tgid:328   ppid:316    flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 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
 __cancel_work_sync kernel/workqueue.c:4411 [inline]
 cancel_work_sync+0xac/0xe0 kernel/workqueue.c:4448
 uhid_dev_destroy drivers/hid/uhid.c:584 [inline]
 uhid_char_release+0xa7/0x600 drivers/hid/uhid.c:662
 __fput+0x208/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e8/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:955
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
 get_signal+0x134c/0x1490 kernel/signal.c:2933
 arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x57/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f57c3b5e399
RSP: 002b:00007f57c3b29178 EFLAGS: 00000246
 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f57c3c0db48 RCX: 00007f57c3b5e399
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f57c3c0db48
RBP: 00007f57c3c0db40 R08: 00007f57c3b29cdc R09: 00007f57c3b29cdc
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f57c3c0db4c
R13: 0000000000000000 R14: 00007ffdda41e2b0 R15: 00007ffdda41e398
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
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:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [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: 64 Comm: kworker/0:2 Not tainted syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events uhid_device_add_worker
RIP: 0010:io_serial_out+0x85/0xd0 drivers/tty/serial/8250/8250_port.c:413
Code: fe 44 89 e1 41 d3 e6 49 83 c7 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 14 3a bd fe 45 03 37 89 d8 44 89 f2 ee <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 e1 80 e1 07
RSP: 0018:ffffc90000d4ee48 EFLAGS: 00000002
RAX: 0000000000000033 RBX: 0000000000000033 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90000d4ee70 R08: ffff888105ea8107 R09: 1ffff11020bd5020
R10: 0000000000000000 R11: ffffffff8322fa20 R12: 0000000000000000
R13: dffffc0000000000 R14: 00000000000003f8 R15: ffffffff88c39488
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555583e22450 CR3: 000000011f410000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 serial_out drivers/tty/serial/8250/8250.h:142 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x16a6/0x2150 drivers/tty/serial/8250/8250_port.c:3427
 univ8250_console_write+0x71/0xb0 drivers/tty/serial/8250/8250_core.c:396
 console_emit_next_record kernel/printk/printk.c:3151 [inline]
 console_flush_all+0x5e6/0xab0 kernel/printk/printk.c:3239
 __console_flush_and_unlock kernel/printk/printk.c:3298 [inline]
 console_unlock+0xf8/0x2c0 kernel/printk/printk.c:3338
 vprintk_emit+0x282/0x650 kernel/printk/printk.c:2462
 dev_vprintk_emit+0x33c/0x400 drivers/base/core.c:4962
 dev_printk_emit+0xef/0x150 drivers/base/core.c:4973
 __dev_printk+0x17f/0x1b0 drivers/base/core.c:4985
 _dev_warn+0x11f/0x180 drivers/base/core.c:5029
 hid_parser_main+0x84d/0xde0 drivers/hid/hid-core.c:667
 hid_open_report+0x87c/0x1120 drivers/hid/hid-core.c:1313
 hid_parse include/linux/hid.h:1139 [inline]
 hid_generic_probe+0x42/0x90 drivers/hid/hid-generic.c:66
 __hid_device_probe drivers/hid/hid-core.c:2760 [inline]
 hid_device_probe+0x2d1/0x5f0 drivers/hid/hid-core.c:2797
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
 __driver_probe_device+0x193/0x280 drivers/base/dd.c:799
 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
 bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
 __device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
 device_add+0x7fd/0xbf0 drivers/base/core.c:3692
 hid_add_device+0x3c4/0x5a0 drivers/hid/hid-core.c:2943
 uhid_device_add_worker+0x49/0xf0 drivers/hid/uhid.c:73
 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: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.963 msecs

Crashes (28):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 04:29 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/07/06 19:37 android16-6.12 87f47a1fd4cf 88b240e4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/06/01 20:20 android16-6.12 266acb5558b2 8d8eeb3a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/05/03 20:31 android16-6.12 8ed163f1fc8c a0d91488 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/09/14 20:26 android16-6.12 0668e45a4339 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/08/31 17:16 android16-6.12 6879524e1c5a 807a3b61 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/07/24 18:19 android16-6.12 379b99745e88 65d60d73 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/06/19 10:49 android16-6.12 30b14cdad458 ed3e87f7 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/07/06 21:51 android16-6.12 87f47a1fd4cf 88b240e4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/07/06 16:42 android16-6.12 87f47a1fd4cf 88b240e4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/02/08 13:48 android16-6.12 6aeca23b5dee 4c131dc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/06/19 13:40 android16-6.12 30b14cdad458 ed3e87f7 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/08/04 12:23 android16-6.12 4f986595e48e 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/06/28 01:01 android16-6.12 220923cf9f76 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/04/28 01:27 android16-6.12 18d3876842e1 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/04/19 02:45 android16-6.12 6532ca3bb1f7 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/04/17 12:49 android16-6.12 100d1d1c17f8 de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/03/27 03:22 android16-6.12 d73a8ddf419e 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/03/06 01:57 android16-6.12 6a6bc2e596fe 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/02/28 01:10 android16-6.12 9791d9d4829d 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2026/02/21 05:57 android16-6.12 7712ca595283 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/11/04 07:03 android16-6.12 0d6730ee6542 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/10/31 11:06 android16-6.12 0d6730ee6542 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/09/02 21:40 android16-6.12 4ae522d0f966 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/07/26 23:18 android16-6.12 e9bbc29c066a fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/07/17 07:57 android16-6.12 3bff0858a069 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/07/15 08:50 android16-6.12 2bd1f3631412 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
2025/07/08 18:13 android16-6.12 15d2fe054444 4d9fdfa4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in uhid_char_release
* Struck through repros no longer work on HEAD.