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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: 36d, last: 1d08h
▶ ▼ 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 (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in uhid_char_release kernel 1 C done 474 1d20h 762d 0/29 upstream: reported C repro on 2023/06/24 03:16
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/07/04 03:58 20m retest repro android16-6.12 report log
2025/07/04 03:58 15m retest repro android16-6.12 report log

Sample crash report:
INFO: task syz-executor280:348 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-g379b99745e88 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor280 state:D
 stack:0     pid:348   tgid:348   ppid:305    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 __flush_work+0x6d2/0xac0 kernel/workqueue.c:4233
 __cancel_work_sync kernel/workqueue.c:4354 [inline]
 cancel_work_sync+0xac/0xe0 kernel/workqueue.c:4391
 uhid_dev_destroy drivers/hid/uhid.c:584 [inline]
 uhid_char_release+0xa7/0x600 drivers/hid/uhid.c:662
 __fput+0x1fb/0xa00 fs/file_table.c:431
 __fput_sync+0x4a/0x70 fs/file_table.c:516
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0x17b/0x240 fs/open.c:1575
 __x64_sys_close+0x3c/0x60 fs/open.c:1575
 x64_sys_call+0x2560/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdf50c754ba
RSP: 002b:00007ffd296b64b0 EFLAGS: 00000293
 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fdf50c754ba
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffd296b6500 R08: 0000000000000000 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000024128
R13: 00007ffd296b6520 R14: 00007fdf50d061b0 R15: 00000000000240f6
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-g379b99745e88 #0 11522de10711ed1cb6b8bd0366ad005e7892f9f5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 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: 322 Comm: kworker/0:3 Not tainted 6.12.30-syzkaller-g379b99745e88 #0 11522de10711ed1cb6b8bd0366ad005e7892f9f5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events uhid_device_add_worker
RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:406
Code: e8 1a 36 6e fe 44 89 f9 d3 e3 49 83 c6 08 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 db 30 c4 fe 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1
RSP: 0018:ffffc9000139edf0 EFLAGS: 00000002
RAX: 1ffffffff113b760 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000139ee10 R08: ffff888107e88107 R09: 1ffff11020fd1020
R10: 0000000000000000 R11: ffffffff831774b0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff889dbda8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e6a9212c0 CR3: 0000000120f46000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:137 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
 wait_for_lsr drivers/tty/serial/8250/8250_port.c:2069 [inline]
 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3315 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3337 [inline]
 serial8250_console_write+0x1392/0x2130 drivers/tty/serial/8250/8250_port.c:3422
 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396
 console_emit_next_record kernel/printk/printk.c:3132 [inline]
 console_flush_all+0x5e6/0xaa0 kernel/printk/printk.c:3220
 __console_flush_and_unlock kernel/printk/printk.c:3279 [inline]
 console_unlock+0xe9/0x270 kernel/printk/printk.c:3319
 vprintk_emit+0x27c/0x640 kernel/printk/printk.c:2443
 dev_vprintk_emit+0x33b/0x400 drivers/base/core.c:4962
 dev_printk_emit+0xe1/0x130 drivers/base/core.c:4973
 __dev_printk+0x17f/0x1b0 drivers/base/core.c:4985
 _dev_warn+0x10b/0x160 drivers/base/core.c:5029
 hid_parser_main+0x84b/0xdc0 drivers/hid/hid-core.c:632
 hid_open_report+0x868/0x1110 drivers/hid/hid-core.c:1278
 hid_parse include/linux/hid.h:1137 [inline]
 hid_generic_probe+0x42/0x90 drivers/hid/hid-generic.c:66
 __hid_device_probe drivers/hid/hid-core.c:2702 [inline]
 hid_device_probe+0x2c4/0x5d0 drivers/hid/hid-core.c:2739
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2d3/0x890 drivers/base/dd.c:657
 __driver_probe_device+0x198/0x280 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+0x25d/0x2f0 drivers/base/bus.c:459
 __device_attach+0x2bd/0x3a0 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+0x80c/0xc00 drivers/base/core.c:3692
 hid_add_device+0x39b/0x560 drivers/hid/hid-core.c:2885
 uhid_device_add_worker+0x49/0xf0 drivers/hid/uhid.c:73
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d5/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
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
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.