Extracting prog: 3m40.355830481s Minimizing prog: 32m53.279340441s Simplifying prog options: 17m1.079334382s Extracting C: 5m20.925294454s Simplifying C: 0s extracting reproducer from 1 programs testing a last program of every proc single: executing 1 programs separately with timeout 6m0s testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release single: successfully extracted reproducer found reproducer with 2 syscalls minimizing guilty program testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid detailed listing: executing program 0: openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) program did not crash testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): write$UHID_CREATE detailed listing: executing program 0: write$UHID_CREATE(0xffffffffffffffff, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program did not crash testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, 0x0, 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program did not crash testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, 0x0, 0x0) program did not crash testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', 0x0, 0x0, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program did not crash extracting C reproducer testing compiled C program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE program crashed: no output from test machine a never seen crash title: no output from test machine, ignore simplifying guilty program options testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release extracting C reproducer testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE program crashed: no output from test machine a never seen crash title: no output from test machine, ignore testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release extracting C reproducer testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE program crashed: no output from test machine a never seen crash title: no output from test machine, ignore testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release validation run: crashed=true testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release validation run: crashed=true testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$uhid-write$UHID_CREATE detailed listing: executing program 0: r0 = openat$uhid(0xffffffffffffff9c, &(0x7f0000003380), 0x2, 0x0) write$UHID_CREATE(r0, &(0x7f00000043c0)={0x0, {'syz0\x00', 'syz1\x00', 'syz1\x00', &(0x7f00000033c0)=""/4096, 0x1000, 0x6, 0x2, 0x6, 0x200, 0xc59}}, 0x120) program crashed: INFO: task hung in uhid_char_release validation run: crashed=true reproducing took 1h9m9.902497456s repro crashed as (corrupted=false): INFO: task syz.3.19:411 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.19 state:D stack:0 pid:411 tgid:411 ppid:401 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 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+0x369/0x650 kernel/sched/completion.c:127 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148 __flush_work+0x712/0xb10 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:429 ____fput+0x20/0x30 fs/file_table.c:457 task_work_run+0x1e5/0x260 kernel/task_work.c:246 resume_user_mode_work+0x35/0x50 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x63/0xb0 kernel/entry/common.c:218 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fdef439aeb9 RSP: 002b:00007ffc8846a138 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007ffc8846a220 RCX: 00007fdef439aeb9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000002a041 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2d020000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdef4615fac R14: 00007fdef4615fa8 R15: 00007fdef4615fa0 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e538f3f6a543b135812147031d083fd1f2699041 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: __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+0xdad/0xf00 kernel/hung_task.c:423 kthread+0x2c9/0x370 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 65 Comm: kworker/0:2 Not tainted syzkaller #0 e538f3f6a543b135812147031d083fd1f2699041 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: events uhid_device_add_worker RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:406 Code: e8 6a 9c 64 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 9b 67 bc fe 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f 5d e9 45 0f 7e 02 cc 44 89 f9 80 e1 RSP: 0018:ffffc90000d5ee10 EFLAGS: 00000006 RAX: 1ffffffff1182405 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc90000d5ee30 R08: 0000000000000003 R09: 0000000000000004 R10: 0000000000000000 R11: ffffffff83230050 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff88c12508 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055988a7b2620 CR3: 000000010cb68000 CR4: 00000000003526b0 Call Trace: serial_port_in include/linux/serial_core.h:794 [inline] serial8250_console_write+0x33a/0x21a0 drivers/tty/serial/8250/8250_port.c:3385 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396 console_emit_next_record kernel/printk/printk.c:3151 [inline] console_flush_all+0x5fa/0xac0 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+0x359/0x420 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+0x84b/0xdc0 drivers/hid/hid-core.c:664 hid_open_report+0x876/0x1110 drivers/hid/hid-core.c:1310 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:2703 [inline] hid_device_probe+0x2c4/0x5d0 drivers/hid/hid-core.c:2740 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d5/0x890 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+0x264/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 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+0x80c/0xbf0 drivers/base/core.c:3692 hid_add_device+0x39b/0x560 drivers/hid/hid-core.c:2886 uhid_device_add_worker+0x49/0xf0 drivers/hid/uhid.c:73 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c9/0x370 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 final repro crashed as (corrupted=false): INFO: task syz.3.19:411 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.19 state:D stack:0 pid:411 tgid:411 ppid:401 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 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+0x369/0x650 kernel/sched/completion.c:127 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148 __flush_work+0x712/0xb10 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:429 ____fput+0x20/0x30 fs/file_table.c:457 task_work_run+0x1e5/0x260 kernel/task_work.c:246 resume_user_mode_work+0x35/0x50 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x63/0xb0 kernel/entry/common.c:218 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fdef439aeb9 RSP: 002b:00007ffc8846a138 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007ffc8846a220 RCX: 00007fdef439aeb9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000002a041 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2d020000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdef4615fac R14: 00007fdef4615fa8 R15: 00007fdef4615fa0 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e538f3f6a543b135812147031d083fd1f2699041 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: __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+0xdad/0xf00 kernel/hung_task.c:423 kthread+0x2c9/0x370 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 65 Comm: kworker/0:2 Not tainted syzkaller #0 e538f3f6a543b135812147031d083fd1f2699041 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: events uhid_device_add_worker RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:406 Code: e8 6a 9c 64 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 9b 67 bc fe 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f 5d e9 45 0f 7e 02 cc 44 89 f9 80 e1 RSP: 0018:ffffc90000d5ee10 EFLAGS: 00000006 RAX: 1ffffffff1182405 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc90000d5ee30 R08: 0000000000000003 R09: 0000000000000004 R10: 0000000000000000 R11: ffffffff83230050 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff88c12508 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055988a7b2620 CR3: 000000010cb68000 CR4: 00000000003526b0 Call Trace: serial_port_in include/linux/serial_core.h:794 [inline] serial8250_console_write+0x33a/0x21a0 drivers/tty/serial/8250/8250_port.c:3385 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396 console_emit_next_record kernel/printk/printk.c:3151 [inline] console_flush_all+0x5fa/0xac0 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+0x359/0x420 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+0x84b/0xdc0 drivers/hid/hid-core.c:664 hid_open_report+0x876/0x1110 drivers/hid/hid-core.c:1310 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:2703 [inline] hid_device_probe+0x2c4/0x5d0 drivers/hid/hid-core.c:2740 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d5/0x890 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+0x264/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 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+0x80c/0xbf0 drivers/base/core.c:3692 hid_add_device+0x39b/0x560 drivers/hid/hid-core.c:2886 uhid_device_add_worker+0x49/0xf0 drivers/hid/uhid.c:73 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c9/0x370 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