INFO: task kworker/u8:7:4593 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7 state:D stack:22968 pid:4593 tgid:4593 ppid:2 task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
io_schedule+0x8a/0xf0 kernel/sched/core.c:7791
rq_qos_wait+0x22d/0x330 block/blk-rq-qos.c:307
__wbt_wait block/blk-wbt.c:596 [inline]
wbt_wait+0x18a/0x310 block/blk-wbt.c:656
__rq_qos_throttle+0x56/0xa0 block/blk-rq-qos.c:66
rq_qos_throttle block/blk-rq-qos.h:164 [inline]
rq_qos_throttle block/blk-rq-qos.h:160 [inline]
blk_mq_get_new_requests block/blk-mq.c:3053 [inline]
blk_mq_submit_bio+0xb6b/0x2b60 block/blk-mq.c:3204
__submit_bio+0x3f0/0x6c0 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x50f/0xbb0 block/blk-core.c:755
submit_bio_noacct+0xb5c/0x1e80 block/blk-core.c:879
ext4_io_submit fs/ext4/page-io.c:404 [inline]
io_submit_add_bh fs/ext4/page-io.c:445 [inline]
ext4_bio_write_folio+0x7ec/0x2000 fs/ext4/page-io.c:589
mpage_process_page_bufs+0x473/0x8d0 fs/ext4/inode.c:2198
mpage_prepare_extent_to_map+0xb50/0x1920 fs/ext4/inode.c:2737
ext4_do_writepages+0xa07/0x3df0 fs/ext4/inode.c:2878
ext4_writepages+0x347/0x790 fs/ext4/inode.c:3026
do_writepages+0x278/0x600 mm/page-writeback.c:2598
__writeback_single_inode+0x164/0x13c0 fs/fs-writeback.c:1737
writeback_sb_inodes+0x72e/0x1b90 fs/fs-writeback.c:2030
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2107
wb_writeback+0x6b4/0xab0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0x885/0xbb0 fs/fs-writeback.c:2403
process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
INFO: task syz.0.51:6521 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.51 state:D stack:28472 pid:6521 tgid:6521 ppid:6384 task_flags:0x440040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
io_schedule+0x8a/0xf0 kernel/sched/core.c:7791
bit_wait_io+0xd/0xe0 kernel/sched/wait_bit.c:250
__wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0xdc/0x110 kernel/sched/wait_bit.c:67
wait_on_bit_io include/linux/wait_bit.h:105 [inline]
do_get_write_access+0x82f/0x1190 fs/jbd2/transaction.c:1092
jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1242
__ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241
ext4_reserve_inode_write+0x1b7/0x330 fs/ext4/inode.c:6290
__ext4_mark_inode_dirty+0x18f/0x840 fs/ext4/inode.c:6465
ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6502
__mark_inode_dirty+0x1ec/0x1560 fs/fs-writeback.c:2595
generic_update_time+0xcf/0xf0 fs/inode.c:2158
inode_update_time fs/inode.c:2171 [inline]
file_update_time_flags+0x401/0x510 fs/inode.c:2398
ext4_page_mkwrite+0x35b/0x1980 fs/ext4/inode.c:6668
do_page_mkwrite+0x17a/0x440 mm/memory.c:3531
do_shared_fault mm/memory.c:5834 [inline]
do_fault+0x3d7/0x1990 mm/memory.c:5896
do_pte_missing mm/memory.c:4404 [inline]
handle_pte_fault mm/memory.c:6276 [inline]
__handle_mm_fault+0x1807/0x2b50 mm/memory.c:6414
handle_mm_fault+0x36d/0xa20 mm/memory.c:6583
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f26ff665bcb
RSP: 002b:00007ffdf46bd8f0 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b32b20000 RSI: 0000000000040000 RDI: 00007f26ff982710
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000023638 R15: 00007ffdf46bdb80
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:7/4593:
#0: ffff88801f2cb948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc9000e8b7c98 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffff888034e960e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:563
#3: ffff888034f30b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x278/0x600 mm/page-writeback.c:2598
2 locks held by getty/5586:
#0: ffff88814eaff0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
3 locks held by syz.0.51/6521:
#0: ffff888030185308 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x5a0 mm/mmap_lock.c:259
#1: ffff888034e96518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x17a/0x440 mm/memory.c:3531
#2: ffff888034f32950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfaa/0x13a0 fs/jbd2/transaction.c:444
3 locks held by syz-executor/6522:
#0: ffff888034e96420 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4881
#1: ffff88806d186420 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline]
#1: ffff88806d186420 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2873 [inline]
#1: ffff88806d186420 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2884 [inline]
#1: ffff88806d186420 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1c0/0x400 fs/namei.c:4888
#2: ffff888034f32950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfaa/0x13a0 fs/jbd2/transaction.c:444
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
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 01/13/2026
RIP: 0010:__to_kthread kernel/kthread.c:101 [inline]
RIP: 0010:kthread_is_per_cpu+0x37/0xf0 kernel/kthread.c:683
Code: 00 48 8d bb f0 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 aa 00 00 00 48 8b ab f0 06 00 00 <48> 85 ed 0f 84 83 00 00 00 e8 1b 74 36 00 48 8d 7b 2c 48 b8 00 00
RSP: 0018:ffffc90000007a88 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff88801e2b5b80 RCX: 0000000000000001
RDX: 1ffff11003c56c4e RSI: ffffffff81cfd62e RDI: ffff88801e2b6270
RBP: ffff88801c69d000 R08: 0000000000000000 R09: ffffc90000007c44
R10: ffff88801e2b5b80 R11: 0000000000000001 R12: 0000000000000007
R13: ffff8880b853adc0 R14: ffff88801e2b614c R15: ffffc90000007c30
FS: 0000000000000000(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558f795cca38 CR3: 000000000e392000 CR4: 00000000003526f0
Call Trace:
can_migrate_task+0x299/0x2500 kernel/sched/fair.c:9450
detach_tasks kernel/sched/fair.c:9623 [inline]
sched_balance_rq+0xfb0/0x36b0 kernel/sched/fair.c:11874
sched_balance_domains+0x46d/0xd40 kernel/sched/fair.c:12295
_nohz_idle_balance.isra.0+0x611/0x840 kernel/sched/fair.c:12727
handle_softirqs+0x1ea/0x910 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xef/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:704
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: a6 7a 02 c3 cc cc cc cc 0f 1f 00 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 23 7b 17 00 fb f4 fc 31 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e207e00 EFLAGS: 00000246
RAX: 000000000014f871 RBX: ffffffff8e297ac0 RCX: ffffffff8b7404b5
RDX: 0000000000000000 RSI: ffffffff8dc413ca RDI: ffffffff8bfa32a0
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed101708673d
R10: ffff8880b84339eb R11: 0000000000000000 R12: fffffbfff1c52f58
R13: 0000000000000000 R14: ffffffff90b771d0 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x35b/0x4b0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x251/0x260 init/main.c:757
start_kernel+0x47a/0x480 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x122/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148