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: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 io_schedule+0x88/0xe0 kernel/sched/core.c:8786
 bit_wait_io+0x17/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xb3/0x2e0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x139/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x558/0xd70 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x268/0x3d0 fs/jbd2/transaction.c:1245
 __ext4_journal_get_write_access+0x1b6/0x6a0 fs/ext4/ext4_jbd2.c:239
 ext4_mb_mark_context+0x393/0xee0 fs/ext4/mballoc.c:4107
 ext4_mb_mark_diskspace_used+0x3aa/0x830 fs/ext4/mballoc.c:4223
 ext4_mb_new_blocks+0x840/0x36c0 fs/ext4/mballoc.c:6318
 ext4_ext_map_blocks+0x14d9/0x6080 fs/ext4/extents.c:4437
 ext4_map_create_blocks fs/ext4/inode.c:520 [inline]
 ext4_map_blocks+0x873/0x17f0 fs/ext4/inode.c:706
 mpage_map_one_extent fs/ext4/inode.c:2222 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2275 [inline]
 ext4_do_writepages+0x1c4a/0x39f0 fs/ext4/inode.c:2738
 ext4_writepages+0x28c/0x550 fs/ext4/inode.c:2827
 do_writepages+0x3d4/0x7f0 mm/page-writeback.c:2689
 __writeback_single_inode+0xc8/0xba0 fs/fs-writeback.c:1674
 writeback_sb_inodes+0x6a5/0xfb0 fs/fs-writeback.c:1970
 __writeback_inodes_wb+0x129/0x280 fs/fs-writeback.c:2041
 wb_writeback+0x3bb/0x850 fs/fs-writeback.c:2152
 wb_check_old_data_flush fs/fs-writeback.c:2256 [inline]
 wb_do_writeback fs/fs-writeback.c:2309 [inline]
 wb_workfn+0xa03/0xef0 fs/fs-writeback.c:2337
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c7/0x360 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>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 55bf8b22bdada172f4c106b01602b1dfb2209583
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: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+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c7/0x360 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: 310 Comm: sshd-session Not tainted syzkaller #0 55bf8b22bdada172f4c106b01602b1dfb2209583
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x4/0x1d
Code: 5b 41 5a 41 59 41 58 5f 5e 5a 59 5d e9 55 30 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <55> 48 89 e5 52 b8 01 00 00 00 31 d2 f0 0f b0 17 75 07 5a 5d c3 cc
RSP: 0018:ffffc9000110f390 EFLAGS: 00000086
RAX: 1ffffffff0e9d1f8 RBX: 0000000000000a02 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000a02 RDI: ffff8881f6f2adc0
RBP: ffffc9000110f3a8 R08: ffff8881f6f2adef R09: 1ffff1103ede55bd
R10: dffffc0000000000 R11: ffffed103ede55be R12: 00000000ffffec4a
R13: 0000000000000001 R14: ffff888120a44aa0 R15: ffff8881f6f2adc0
FS:  00007f6dcfd99300(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 00000001288aa000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 __mod_timer+0x881/0xd20 kernel/time/timer.c:1189
 mod_timer+0x23/0x30 kernel/time/timer.c:1245
 sk_reset_timer+0x26/0xc0 net/core/sock.c:3562
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:-1 [inline]
 tcp_reset_xmit_timer include/net/tcp.h:1445 [inline]
 tcp_rearm_rto+0x307/0x710 net/ipv4/tcp_input.c:3311
 tcp_event_new_data_sent+0x22a/0x3c0 net/ipv4/tcp_output.c:84
 tcp_write_xmit+0x1a64/0x6d20 net/ipv4/tcp_output.c:2857
 __tcp_push_pending_frames+0x9d/0x300 net/ipv4/tcp_output.c:3035
 tcp_push+0x488/0x670 net/ipv4/tcp.c:755
 tcp_sendmsg_locked+0x3fce/0x4ac0 net/ipv4/tcp.c:1332
 tcp_sendmsg+0x3e/0xd0 net/ipv4/tcp.c:1365
 inet_sendmsg+0xb7/0x120 net/ipv4/af_inet.c:858
 sock_sendmsg_nosec net/socket.c:731 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_write_iter+0x3bf/0x490 net/socket.c:1166
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x75f/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0033:0x7f6dcf6a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdc5901570 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6dcfd99300 RCX: 00007f6dcf6a7407
RDX: 000000000000007c RSI: 000055cb9cdf3030 RDI: 0000000000000004
RBP: 000055cb9cdf1c60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001
R13: 00007ffdc59016c0 R14: 0000000000000000 R15: 0000000000000004
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs