INFO: task kworker/u8:0:13 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/u8:0 state:D stack:21768 pid:13 tgid:13 ppid:2 task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
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_lock+0xc9/0x5a0 kernel/sched/wait_bit.c:93
out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
lock_buffer include/linux/buffer_head.h:488 [inline]
do_get_write_access+0x1b7/0x10c0 fs/jbd2/transaction.c:969
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+0x171/0xec0 fs/ext4/mballoc.c:4110
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
Showing all locks held in the system:
locks held by kworker/u8:0/13: 6, on CPU#1:
#0: ffff888021a9c948 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021a9c948 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021a9c948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff888021a9c948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#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:3460 [inline]
#1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff888038670100 (&type->s_umount_key#34){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:642
#3: ffff888038668cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f1/0x4e0 fs/ext4/inode.c:3170
#4: ffff888038306950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444
#5: ffff888013680b28 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0xacb/0x1c60 fs/ext4/inode.c:926
locks held by khungtaskd/36: 1, last CPU#0:
#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 getty/5395: 2, on CPU#1:
#0: ffff8880347300a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032362e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5625: 2, on CPU#1:
#0: ffff8880279ca948 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863
locks held by kworker/u9:4/5645: 2, on CPU#0:
#0: ffff888028b42148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888028b42148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888028b42148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff888028b42148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90003ecfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90003ecfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90003ecfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90003ecfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
locks held by syz.3.386/6978: 2, on CPU#1:
#0: ffff888055678588 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863
locks held by syz.1.389/6986: 2, on CPU#1:
#0: ffff88802c58c948 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863
locks held by syz.4.390/6989: 2, on CPU#0:
#0: ffff88802faa6948 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff888038670570 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863
locks held by syz.2.392/6992: 2, on CPU#1:
#0: ffff888023345900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline]
#0: ffff888023345900 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579
#1: ffff888038670478 (sb_writers#4){++++}-{0:0}, at: file_accessed include/linux/fs.h:2283 [inline]
#1: ffff888038670478 (sb_writers#4){++++}-{0:0}, at: ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919
locks held by syz.0.393/6993: 2, on CPU#1:
#0: ffff888023340f80 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline]
#0: ffff888023340f80 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579
#1: ffff888038670478 (sb_writers#4){++++}-{0:0}, at: file_accessed include/linux/fs.h:2283 [inline]
#1: ffff888038670478 (sb_writers#4){++++}-{0:0}, at: ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 36 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
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
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 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: 3b 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 db 24 00 fb f4 3c 17 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc900001c7e40 EFLAGS: 00000242
RAX: 0000000000125fb9 RBX: ffffffff819ca3e0 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8e6a8d60 RDI: ffffffff8c8ea380
RBP: ffffc900001c7f10 R08: ffff8880b8333d9b R09: 1ffff110170667b3
R10: dffffc0000000000 R11: ffffed10170667b4 R12: 0000000000000000
R13: 1ffff11003e5e3e8 R14: 1ffff92000038fd0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88812350d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559972006168 CR3: 000000000ff48000 CR4: 00000000003526f0
Call Trace:
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
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x157