syzbot

INFO: task udevd:7053 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:0     pid:7053  tgid:7053  ppid:110    flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 io_schedule+0x89/0xe0 kernel/sched/core.c:8699
 folio_wait_bit_common+0x6ae/0x910 mm/filemap.c:1354
 __folio_lock mm/filemap.c:1731 [inline]
 folio_lock include/linux/pagemap.h:1158 [inline]
 __filemap_get_folio+0x17c/0xaa0 mm/filemap.c:1987
 truncate_inode_pages_range+0x3e0/0xb50 mm/truncate.c:356
 truncate_inode_pages+0x28/0x40 mm/truncate.c:431
 kill_bdev block/bdev.c:92 [inline]
 blkdev_flush_mapping+0x10e/0x290 block/bdev.c:693
 blkdev_put_whole block/bdev.c:700 [inline]
 bdev_release+0x433/0x690 block/bdev.c:1125
 blkdev_release+0x19/0x30 block/fops.c:635
 __fput+0x1fe/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e0/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9bc/0x2630 kernel/exit.c:953
 do_group_exit+0x22a/0x300 kernel/exit.c:1095
 get_signal+0x139d/0x14f0 kernel/signal.c:2933
 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f79e36a7407
RSP: 002b:00007ffe98da14e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: fffffffffffffffc RBX: 00007f79e3d67880 RCX: 00007f79e36a7407
RDX: 0000000000000200 RSI: 00007f79e3d55000 RDI: 0000000000000009
RBP: 0000558538181770 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000558538183908 R15: 00007f79e3e2c39c
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 1f5813a52420658c51670c32aa0b3f2b32c06bdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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+0x2ca/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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20788 Comm: syz-executor Not tainted syzkaller #0 1f5813a52420658c51670c32aa0b3f2b32c06bdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rdtsc_ordered arch/x86/include/asm/msr.h:217 [inline]
RIP: 0010:__pvclock_clocksource_read arch/x86/kernel/pvclock.c:77 [inline]
RIP: 0010:pvclock_clocksource_read_nowd+0x4b/0x100 arch/x86/kernel/pvclock.c:120
Code: f1 48 d3 e0 41 83 e7 fe 4c 89 65 d0 48 f7 65 d0 48 0f ac d0 20 48 8b 4f 10 0f b6 57 1d 8b 37 41 39 f7 41 89 f7 74 70 0f 01 f9 <66> 90 48 89 c1 48 89 d0 48 c1 e0 20 48 09 c8 48 2b 47 08 44 8b 67
RSP: 0018:ffffc90001cd7400 EFLAGS: 00000087
RAX: 0000000022d2d34c RBX: dffffc0000000000 RCX: 0000000000000001
RDX: 0000000000000181 RSI: 0000000000000004 RDI: ffffffff88970040
RBP: ffffc90001cd7430 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200039aebc R12: ffff8881f6f4f980
R13: dffffc0000000000 R14: ffffc90001cd74e0 R15: 0000000000000008
FS:  00005555694cb500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000514ff4 CR3: 00000001232ea000 CR4: 00000000003526b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_sched_clock_read+0x15/0x30 arch/x86/kernel/kvmclock.c:91
 paravirt_sched_clock arch/x86/include/asm/paravirt.h:35 [inline]
 sched_clock_noinstr+0xd/0x30 arch/x86/kernel/tsc.c:267
 sched_clock+0x1c/0x60 arch/x86/kernel/tsc.c:284
 sched_clock_cpu+0x75/0x400 kernel/sched/clock.c:394
 update_rq_clock+0xbf/0x7c0 kernel/sched/core.c:856
 sched_balance_update_blocked_averages+0x125/0x1320 kernel/sched/fair.c:10169
 sched_balance_newidle+0x366/0xda0 kernel/sched/fair.c:13136
 pick_next_task_fair+0xd8/0x990 kernel/sched/fair.c:9183
 __pick_next_task kernel/sched/core.c:6605 [inline]
 pick_next_task kernel/sched/core.c:7125 [inline]
 __schedule+0x65d/0x1df0 kernel/sched/core.c:7718
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 do_nanosleep+0x164/0x590 kernel/time/hrtimer.c:2094
 hrtimer_nanosleep+0x13e/0x320 kernel/time/hrtimer.c:2142
 common_nsleep+0x93/0xb0 kernel/time/posix-timers.c:1373
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1419 [inline]
 __se_sys_clock_nanosleep+0x2fd/0x390 kernel/time/posix-timers.c:1396
 __x64_sys_clock_nanosleep+0x9f/0xc0 kernel/time/posix-timers.c:1396
 x64_sys_call+0x2554/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:231
 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: 0033:0x7f7e36bc1743
Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d 1e 6e 1f 00 00 74 14 b8 e6 00 00 00 0f 05 <f7> d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10
RSP: 002b:00007ffc23645948 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000219 RCX: 00007f7e36bc1743
RDX: 00007ffc23645960 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc236459cc R08: 0000000022cb4ac9 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000a2
R13: 0000000000000034 R14: 00000000000b6736 R15: 00007ffc23645a20
 </TASK>