INFO: task syz.3.20:525 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D stack:0     pid:525   tgid:524   ppid:485    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134a/0x1dd0 kernel/sched/core.c:7842
 __schedule_loop kernel/sched/core.c:7923 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7938
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7995
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:911 [inline]
 usbdev_open+0x16b/0x800 drivers/usb/core/devio.c:1051
 chrdev_open+0x4dc/0x600 fs/char_dev.c:414
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2bb1/0x34f0 fs/namei.c:3941
 do_filp_open+0x1f5/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0033:0x7f744535ae0e
RSP: 002b:00007f74461c0b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f74461c16c0 RCX: 00007f744535ae0e
RDX: 0000000000000002 RSI: 00007f74461c0c00 RDI: ffffffffffffff9c
RBP: 00007f74461c0c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f7445606038 R14: 00007f7445605fa0 R15: 00007ffdc2ad6738
 </TASK>
INFO: task syz.0.17:527 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:0     pid:527   tgid:526   ppid:484    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134a/0x1dd0 kernel/sched/core.c:7842
 __schedule_loop kernel/sched/core.c:7923 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7938
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7995
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:911 [inline]
 usbdev_open+0x16b/0x800 drivers/usb/core/devio.c:1051
 chrdev_open+0x4dc/0x600 fs/char_dev.c:414
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2bb1/0x34f0 fs/namei.c:3941
 do_filp_open+0x1f5/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0033:0x7effe6f5ae0e
RSP: 002b:00007effe7d5db28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007effe7d5e6c0 RCX: 00007effe6f5ae0e
RDX: 0000000000000002 RSI: 00007effe7d5dc00 RDI: ffffffffffffff9c
RBP: 00007effe7d5dc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007effe7206038 R14: 00007effe7205fa0 R15: 00007ffe3a843b68
 </TASK>
INFO: task syz.4.18:529 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.18        state:D stack:0     pid:529   tgid:528   ppid:487    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134a/0x1dd0 kernel/sched/core.c:7842
 __schedule_loop kernel/sched/core.c:7923 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7938
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7995
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:911 [inline]
 usbdev_open+0x16b/0x800 drivers/usb/core/devio.c:1051
 chrdev_open+0x4dc/0x600 fs/char_dev.c:414
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2bb1/0x34f0 fs/namei.c:3941
 do_filp_open+0x1f5/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0033:0x7f0e73d5ae0e
RSP: 002b:00007f0e74c9cb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0e74c9d6c0 RCX: 00007f0e73d5ae0e
RDX: 0000000000000002 RSI: 00007f0e74c9cc00 RDI: ffffffffffffff9c
RBP: 00007f0e74c9cc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f0e74006038 R14: 00007f0e74005fa0 R15: 00007ffefbda7078
 </TASK>
INFO: task syz.5.19:532 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.19        state:D stack:0     pid:532   tgid:531   ppid:486    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134a/0x1dd0 kernel/sched/core.c:7842
 __schedule_loop kernel/sched/core.c:7923 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7938
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7995
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:911 [inline]
 usbdev_open+0x16b/0x800 drivers/usb/core/devio.c:1051
 chrdev_open+0x4dc/0x600 fs/char_dev.c:414
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x240 fs/open.c:1092
 do_open fs/namei.c:3782 [inline]
 path_openat+0x2bb1/0x34f0 fs/namei.c:3941
 do_filp_open+0x1f5/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1466
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0033:0x7f0fe975ae0e
RSP: 002b:00007f0fe95feb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0fe95ff6c0 RCX: 00007f0fe975ae0e
RDX: 0000000000000002 RSI: 00007f0fe95fec00 RDI: ffffffffffffff9c
RBP: 00007f0fe95fec00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f0fe9a06038 R14: 00007f0fe9a05fa0 R15: 00007ffe6c1ac898
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e0dc4740519b93b78861b2341b197f4e1f1066ac
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c6/0x370 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 e0dc4740519b93b78861b2341b197f4e1f1066ac
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x5/0x90 kernel/kcov.c:313
Code: 10 48 89 74 11 18 48 89 44 11 20 5d c3 cc cc cc cc cc 0f 1f 00 b8 60 96 b1 8c 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 15 ec 5e 7d 7e 65 8b 0d ed 5e 7d 7e
RSP: 0018:ffffc90000007e80 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff874156c0
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007fb8 R08: ffffffff874156c0 R09: 0000000000000002
R10: 0000000000000000 R11: ffffffff81427f00 R12: dffffc0000000000
R13: ffff8881f6e2cec0 R14: 7fffffffffffffff R15: 0000002c3489b100
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555576c054e8 CR3: 000000010cb9a000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x8e/0x2a0 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x7d/0x90 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702
RIP: 0010:default_idle_call+0x5b/0x80 kernel/sched/idle.c:126
Code: ab c2 fb e8 f7 f0 ff ff e8 e2 fd ff ff e8 dd f1 ff ff 65 8b 35 92 d2 66 7a bf ff ff ff ff e8 5c ab c2 fb e8 37 ac c2 fb fb 5d <e9> 90 46 02 00 cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 90
RSP: 0018:ffffffff87407dd8 EFLAGS: 00000286
RAX: a4bf88fa4635b600 RBX: ffffffff874156c0 RCX: ffffffff859e0b61
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: ffffffff87407eb0 R08: ffff8881f6e39733 R09: 1ffff1103edc72e6
R10: dffffc0000000000 R11: ffffed103edc72e7 R12: 1ffffffff0e82ad8
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff87ebaca8
 cpu_startup_entry+0x47/0x60 kernel/sched/idle.c:424
 rest_init+0x10b/0x130 init/main.c:760
 start_kernel+0x462/0x4bb init/main.c:1242
 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:507
 x86_64_start_kernel+0x6a/0x7b arch/x86/kernel/head64.c:488
 common_startup_64+0x13b/0x157
 </TASK>