syzbot

INFO: task syz.0.33530:3134 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.33530     state:D stack:0     pid:3134  tgid:3134  ppid:31008  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6016 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7864
 __schedule_loop kernel/sched/core.c:7945 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7960
 request_wait_answer fs/fuse/dev.c:477 [inline]
 __fuse_request_send fs/fuse/dev.c:493 [inline]
 __fuse_simple_request+0xdee/0x1b10 fs/fuse/dev.c:588
 fuse_simple_request fs/fuse/fuse_i.h:1248 [inline]
 fuse_flush+0xad9/0x2020 fs/fuse/file.c:602
 filp_flush fs/open.c:1552 [inline]
 filp_close+0xc0/0x160 fs/open.c:1565
 __range_close fs/file.c:710 [inline]
 __close_range+0x529/0x6e0 fs/file.c:767
 __do_sys_close_range fs/open.c:1618 [inline]
 __se_sys_close_range fs/open.c:1615 [inline]
 __x64_sys_close_range+0x7e/0x90 fs/open.c:1615
 x64_sys_call+0x1686/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:437
 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: 0033:0x7f66ca99c799
RSP: 002b:00007ffcbe16b0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007ffcbe16b1b0 RCX: 00007f66ca99c799
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000ad5ba R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2da20000 R11: 0000000000000246 R12: 00007ffcbe16b1f0
R13: 00007f66cac1609c R14: 00000000000ad689 R15: 00007f66cac16090
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 a88889f1fd4bd040639a1a4060abea1bc20e1fef
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c9/0x370 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 a88889f1fd4bd040639a1a4060abea1bc20e1fef
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:irqtime_account_delta kernel/sched/cputime.c:47 [inline]
RIP: 0010:irqtime_account_irq+0xb4/0x1c0 kernel/sched/cputime.c:-1
Code: 0f 00 74 74 b8 20 00 00 00 65 48 8b 0d fd 5d a0 7e 49 bf 00 00 00 00 00 fc ff df 48 8d 9c 01 20 8d 02 00 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 ad cd 7d 00 4c 01 33 4c 89 e0 48
RSP: 0018:ffffc90000230ef0 EFLAGS: 00000802
RAX: 1ffff1103ede51a7 RBX: ffff8881f6f28d38 RCX: ffff8881f6f00000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90000230f28 R08: ffff88810b6484b7 R09: 0000000000000000
R10: fffff52000046130 R11: ffffed10216c9097 R12: ffff8881f6f28e40
R13: 0000000000000000 R14: 000000000000110d R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc609dfde0 CR3: 000000010d7ea000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 account_softirq_exit include/linux/vtime.h:142 [inline]
 handle_softirqs+0x54d/0x630 kernel/softirq.c:651
 __do_softirq kernel/softirq.c:659 [inline]
 invoke_softirq kernel/softirq.c:476 [inline]
 __irq_exit_rcu+0x47/0xb0 kernel/softirq.c:708
 irq_exit_rcu+0xd/0x30 kernel/softirq.c:720
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0x7f/0x90 arch/x86/kernel/smp.c:266
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x1f/0x30 arch/x86/include/asm/idtentry.h:709
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc cc cc cc cc b8 ac 38 27 2b 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 cb 48 00 55 48 89 e5 fb f4 <5d> e9 07 60 02 00 cc cc cc cc cc cc cc b8 00 00 00 00 90 90 90 90
RSP: 0018:ffffc900001a7e00 EFLAGS: 000002c6
RAX: ffff8881f6f00000 RBX: ffff88810366b900 RCX: ffffffff859e8b2d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000036cec
RBP: ffffc900001a7e00 R08: ffff8881f6f39733 R09: 1ffff1103ede72e6
R10: dffffc0000000000 R11: ffffed103ede72e7 R12: 1ffff110206cd720
R13: 0000000000000001 R14: 0000000000000000 R15: ffffffff87ebd828
 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:754
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:791
 default_idle_call+0x3e/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x19f/0x4b0 kernel/sched/idle.c:326
 cpu_startup_entry+0x47/0x60 kernel/sched/idle.c:424
 start_secondary+0x12e/0x140 arch/x86/kernel/smpboot.c:314
 common_startup_64+0x13b/0x157
 </TASK>