INFO: task kworker/u8:2:46 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2    state:D stack:0     pid:46    tgid:46    ppid:2      flags:0x00004000
Workqueue: loop0 loop_rootcg_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 blk_mq_freeze_queue_wait+0xf3/0x180 block/blk-mq.c:210
 blk_freeze_queue+0xc7/0x100 block/blk-mq.c:237
 blk_mq_freeze_queue+0x19/0x30 block/blk-mq.c:246
 queue_attr_store+0x2c9/0x3d0 block/blk-sysfs.c:703
 sysfs_kf_write+0x13e/0x160 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x316/0x510 fs/kernfs/file.c:352
 lo_rw_aio+0xd36/0x1020 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:447 [inline]
 loop_handle_cmd drivers/block/loop.c:1900 [inline]
 loop_process_work+0x589/0x12c0 drivers/block/loop.c:1935
 loop_rootcg_workfn+0x26/0x40 drivers/block/loop.c:1966
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f4/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c4/0x360 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>
INFO: task syz-executor761:313 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor761 state:D stack:0     pid:313   tgid:313   ppid:312    flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 io_schedule+0x85/0x150 kernel/sched/core.c:8790
 folio_wait_bit_common+0x6a4/0x940 mm/filemap.c:1379
 folio_wait_bit+0x29/0x50 mm/filemap.c:1518
 folio_wait_writeback+0x90/0x1c0 mm/page-writeback.c:3197
 __filemap_fdatawait_range+0x185/0x290 mm/filemap.c:589
 filemap_write_and_wait_range+0x205/0x2a0 mm/filemap.c:750
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev block/bdev.c:241 [inline]
 bdev_release+0x199/0x700 block/bdev.c:1107
 blkdev_release+0x19/0x30 block/fops.c:635
 __fput+0x20b/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e5/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:961
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1104
 __do_sys_exit_group kernel/exit.c:1115 [inline]
 __se_sys_exit_group kernel/exit.c:1113 [inline]
 __x64_sys_exit_group+0x43/0x50 kernel/exit.c:1113
 x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7fc09620b8e5
RSP: 002b:00007ffc891d8638 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fc09620b8e5
RDX: 00000000000000e7 RSI: ffffffffffffffd8 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fc0962a4110 R14: 00007fc0962a63a8 R15: 00007fc0962a63c0
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 249ace596eef83e7ab94f4ef92c49a820648daf1
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:114
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:63
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 cpumask_backtrace+0x1f/0x30 lib/nmi_backtrace.c:127
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c4/0x360 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 249ace596eef83e7ab94f4ef92c49a820648daf1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:116
Code: cc cc cc cc cc cc cc b8 40 cd bf 8e 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 07 42 00 55 48 89 e5 fb f4 <5d> c3 cc cc cc cc cc cc cc cc cc cc cc b8 00 00 00 00 90 90 90 90
RSP: 0018:ffffc900001a7e00 EFLAGS: 000002c2
RAX: ffff8881f6f00000 RBX: ffff88810366b900 RCX: ffffffff85a5553d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000025e9c
RBP: ffffc900001a7e00 R08: ffff8881f6f395eb R09: 1ffff1103ede72bd
R10: dffffc0000000000 R11: ffffed103ede72be R12: 0000000000000000
R13: 1ffff110206cd720 R14: dffffc0000000000 R15: ffffffff87ece328
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004644b0 CR3: 000000010b3c4000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:-1 [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:193 [inline]
 do_idle+0x1df/0x570 kernel/sched/idle.c:346
 cpu_startup_entry+0x47/0x60 kernel/sched/idle.c:445
 start_secondary+0x12e/0x140 arch/x86/kernel/smpboot.c:314
 common_startup_64+0x13b/0x157
 </TASK>