INFO: task kworker/u8:4:65 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:22792 pid:65    tgid:65    ppid:2      task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5583 [inline]
 __schedule+0x17dd/0x5830 kernel/sched/core.c:7382
 __schedule_loop kernel/sched/core.c:7459 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7474
 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146
 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258
 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
 wait_on_bit_io include/linux/wait_bit.h:106 [inline]
 do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113
 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263
 __ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253
 ext4_mb_mark_context+0x325/0xec0 fs/ext4/mballoc.c:4123
 ext4_mb_mark_diskspace_used+0x338/0x760 fs/ext4/mballoc.c:4239
 ext4_mb_new_blocks+0x1062/0x4520 fs/ext4/mballoc.c:6327
 ext4_ext_map_blocks+0x1427/0x5480 fs/ext4/extents.c:4469
 ext4_map_create_blocks+0x116/0x530 fs/ext4/inode.c:697
 ext4_map_blocks+0xe8e/0x1c60 fs/ext4/inode.c:942
 mpage_map_one_extent fs/ext4/inode.c:2505 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2601 [inline]
 ext4_do_writepages+0x1978/0x44a0 fs/ext4/inode.c:3077
 ext4_writepages+0x1fe/0x4e0 fs/ext4/inode.c:3171
 do_writepages+0x338/0x560 mm/page-writeback.c:2562
 __writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1809
 writeback_sb_inodes+0x9de/0x1af0 fs/fs-writeback.c:2120
 __writeback_inodes_wb+0x114/0x250 fs/fs-writeback.c:2196
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2307
 wb_check_old_data_flush fs/fs-writeback.c:2411 [inline]
 wb_do_writeback fs/fs-writeback.c:2490 [inline]
 wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2518
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task jbd2/sda1-8:4968 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8     state:D stack:26280 pid:4968  tgid:4968  ppid:2      task_flags:0x240040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5583 [inline]
 __schedule+0x17dd/0x5830 kernel/sched/core.c:7382
 __schedule_loop kernel/sched/core.c:7459 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7474
 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146
 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258
 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
 wait_on_buffer include/linux/buffer_head.h:476 [inline]
 jbd2_journal_commit_transaction+0x2f6e/0x5c80 fs/jbd2/commit.c:834
 kjournald2+0x3bc/0x740 fs/jbd2/journal.c:200
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/37: 1, last CPU#1:
 #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:4/65: 6, on CPU#1:
 #0: ffff888021e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888021e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888021e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #0: ffff888021e85148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #1: ffffc90001567c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90001567c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90001567c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #1: ffffc90001567c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #2: ffff888037596100 (&type->s_umount_key#34){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:642
 #3: ffff888037580cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f1/0x4e0 fs/ext4/inode.c:3170
 #4: ffff888037594950 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444
 #5: ffff888077968b28 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0xacb/0x1c60 fs/ext4/inode.c:926
locks held by getty/5402: 2, on CPU#0:
 #0: ffff888036e0a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline]
 watchdog+0x1073/0x10f0 kernel/hung_task.c:598
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 4b 93 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 7b 10 00 fb f4 <e9> 3c 17 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8fe07ca0 EFLAGS: 00000246
RAX: 0000000000316533 RBX: ffffffff819cccb0 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8e7e9c25 RDI: ffffffff8c8ff980
RBP: ffffffff8fe07d78 R08: ffff8880b8233d9b R09: 1ffff110170467b3
R10: dffffc0000000000 R11: ffffed10170467b4 R12: 0000000000000000
R13: 1ffffffff1fd1df8 R14: 1ffffffff1fc0f9c R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888123376000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 000000007bf4c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:767 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:768
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x2e0/0x540 kernel/sched/idle.c:355
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:458
 rest_init+0x378/0x3a0 init/main.c:789
 start_kernel+0x392/0x3e0 init/main.c:1247
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x157
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.041 msecs