INFO: task syz.1.103:660 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.103       state:D stack:0     pid:660   tgid:659   ppid:295    flags:0x00004004
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_preempt_disabled+0x14/0x30 kernel/sched/core.c:8029
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:911 [inline]
 usb_device_read+0x176/0x2d0 drivers/usb/core/devices.c:528
 full_proxy_read+0x128/0x1e0 fs/debugfs/file.c:323
 vfs_read+0x288/0xc70 fs/read_write.c:568
 ksys_read+0x145/0x260 fs/read_write.c:713
 __do_sys_read fs/read_write.c:723 [inline]
 __se_sys_read fs/read_write.c:721 [inline]
 __x64_sys_read+0x7f/0x90 fs/read_write.c:721
 x64_sys_call+0x2638/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:1
 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: 0033:0x7fe15e95e90e
RSP: 002b:00007fe15f87af68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fe15f87b6c0 RCX: 00007fe15e95e90e
RDX: 0000000000002000 RSI: 00002000000021c0 RDI: 0000000000000003
RBP: 00007fe15ea35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00002000000002c0 R14: 00007fe15ec25fa0 R15: 00007ffd7f816f48
 </TASK>
INFO: task syz.4.141:791 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.141       state:D stack:0     pid:791   tgid:790   ppid:765    flags:0x00000004
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_preempt_disabled+0x14/0x30 kernel/sched/core.c:8029
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 usb_device_read+0xe6/0x2d0 drivers/usb/core/devices.c:522
 full_proxy_read+0x128/0x1e0 fs/debugfs/file.c:323
 vfs_read+0x288/0xc70 fs/read_write.c:568
 ksys_read+0x145/0x260 fs/read_write.c:713
 __do_sys_read fs/read_write.c:723 [inline]
 __se_sys_read fs/read_write.c:721 [inline]
 __x64_sys_read+0x7f/0x90 fs/read_write.c:721
 x64_sys_call+0x2638/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:1
 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: 0033:0x7fd16bd5e90e
RSP: 002b:00007fd16ccf0f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd16ccf16c0 RCX: 00007fd16bd5e90e
RDX: 0000000000002015 RSI: 00002000000021c0 RDI: 0000000000000003
RBP: 00007fd16be35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00002000000002c0 R14: 00007fd16c025fa0 R15: 00007ffdcb101618
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 f2f9be0cb5819eb91f3cdfab905957d5e4b40d7b
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>