INFO: task kworker/u8:1:13 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/u8:1    state:D stack:23200 pid:13    tgid:13    ppid:2      task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7362
 io_schedule+0x80/0xe0 kernel/sched/core.c:8190
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:258
 __wait_on_bit+0xac/0x2f0 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+0x671/0x1090 fs/jbd2/transaction.c:1113
 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263
 __ext4_journal_get_write_access+0xf1/0x620 fs/ext4/ext4_jbd2.c:249
 ext4_mb_mark_context+0x325/0xec0 fs/ext4/mballoc.c:4125
 ext4_mb_mark_diskspace_used+0x338/0x760 fs/ext4/mballoc.c:4241
 ext4_mb_new_blocks+0x106f/0x4540 fs/ext4/mballoc.c:6329
 ext4_ext_map_blocks+0x13f1/0x5680 fs/ext4/extents.c:4469
 ext4_map_create_blocks+0x116/0x530 fs/ext4/inode.c:630
 ext4_map_blocks+0x791/0x12c0 fs/ext4/inode.c:823
 mpage_map_one_extent fs/ext4/inode.c:2379 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2469 [inline]
 ext4_do_writepages+0x239b/0x4770 fs/ext4/inode.c:2938
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3032
 do_writepages+0x338/0x560 mm/page-writeback.c:2560
 __writeback_single_inode+0x136/0x1230 fs/fs-writeback.c:1788
 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2099
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2175
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2286
 wb_check_old_data_flush fs/fs-writeback.c:2390 [inline]
 wb_do_writeback fs/fs-writeback.c:2469 [inline]
 wb_workfn+0xc98/0x10f0 fs/fs-writeback.c:2497
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/0x470 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/sda1-8:4919 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:25160 pid:4919  tgid:4919  ppid:2      task_flags:0x240040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7362
 io_schedule+0x80/0xe0 kernel/sched/core.c:8190
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:258
 __wait_on_bit+0xac/0x2f0 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:418 [inline]
 jbd2_journal_commit_transaction+0x2f26/0x5ba0 fs/jbd2/commit.c:834
 kjournald2+0x3bc/0x750 fs/jbd2/journal.c:200
 kthread+0x38b/0x470 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 kworker/u8:1/13: 6, on CPU#1:
 #0: ffff88801d6d4938 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801d6d4938 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801d6d4938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #0: ffff88801d6d4938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #2: ffff88803719e0e0 (&type->s_umount_key#34){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:688
 #3: ffff888037188d98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
 #3: ffff888037188d98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1887 [inline]
 #3: ffff888037188d98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3031
 #4: ffff88803719abb0 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0x1fbf/0x2200 fs/jbd2/transaction.c:444
 #5: ffff888040960dd0 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0x77d/0x12c0 fs/ext4/inode.c:822
locks held by pr/ttyS0/17: 3, last CPU#0:
 #0: ffffffff8e09d578 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
 #0: ffffffff8e09d578 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
 #0: ffffffff8e09d578 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
 #1: ffffffff99e971f8 (&port_lock_key){+.+.}-{3:3}, at: nbcon_emit_one kernel/printk/nbcon.c:1137 [inline]
 #1: ffffffff99e971f8 (&port_lock_key){+.+.}-{3:3}, at: nbcon_kthread_func+0x64c/0x880 kernel/printk/nbcon.c:1271
 #2: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #2: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by khungtaskd/38: 1, last CPU#1:
 #0: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1c3ac0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837
locks held by kworker/u8:8/982: 2, on CPU#0:
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #1: ffffc90005d87c40 ((reaper_work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90005d87c40 ((reaper_work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90005d87c40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #1: ffffc90005d87c40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
locks held by kworker/u8:15/1438: 2, on CPU#0:
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #1: ffffc90006ebfc40 (connector_reaper_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90006ebfc40 (connector_reaper_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90006ebfc40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #1: ffffc90006ebfc40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
locks held by getty/5350: 2, on CPU#0:
 #0: ffff8880371430a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900044cb2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x38b/0x470 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: 17 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:delay_tsc+0x5d/0xd0 arch/x86/lib/delay.c:77
Code: 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 55 bf 01 00 00 00 e8 42 b7 40 f6 65 48 8b 05 6a b7 50 07 48 85 c0 74 1c f3 90 <bf> 01 00 00 00 e8 d9 b5 40 f6 e8 14 79 01 00 39 c5 75 0e 0f 01 f9
RSP: 0018:ffffc900001678b8 EFLAGS: 00000286
RAX: 8000000000000000 RBX: 0000000000000899 RCX: ffffffff99ade501
RDX: 0000000000000001 RSI: ffffffff8bcc2060 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8b53e850 R12: 1ffffffff33d2e99
R13: 00000000ffffffff R14: 000000df917b8c8e R15: 0000000000000182
FS:  0000000000000000(0000) GS:ffff888125bd6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fee547da000 CR3: 000000000dfb0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 udelay include/asm-generic/delay.h:62 [inline]
 wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:2019
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline]
 __serial8250_console_fifo_write+0xd0/0x3f0 drivers/tty/serial/8250/8250_port.c:3345
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
 __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
 serial8250_console_write+0xac5/0x1230 drivers/tty/serial/8250/8250_port.c:3493
 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
 nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271
 kthread+0x38b/0x470 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>