INFO: task kworker/u8:6:2912 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6 state:D stack:23560 pid:2912 tgid:2912 ppid:2 task_flags:0x4248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
io_schedule+0xbf/0x130 kernel/sched/core.c:7903
rq_qos_wait+0x22f/0x340 block/blk-rq-qos.c:307
__wbt_wait block/blk-wbt.c:596 [inline]
wbt_wait+0x1af/0x390 block/blk-wbt.c:656
__rq_qos_throttle+0x56/0xa0 block/blk-rq-qos.c:66
rq_qos_throttle block/blk-rq-qos.h:168 [inline]
rq_qos_throttle block/blk-rq-qos.h:163 [inline]
blk_mq_get_new_requests block/blk-mq.c:3033 [inline]
blk_mq_submit_bio+0x2174/0x2a10 block/blk-mq.c:3183
__submit_bio+0x3cf/0x690 block/blk-core.c:635
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x660/0xd30 block/blk-core.c:751
submit_bio_noacct+0xc20/0x1ed0 block/blk-core.c:874
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+0x756/0x1dc0 fs/ext4/page-io.c:589
mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2191
mpage_prepare_extent_to_map+0x79f/0x14d0 fs/ext4/inode.c:2736
ext4_do_writepages+0xa11/0x3cf0 fs/ext4/inode.c:2877
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3025
do_writepages+0x27a/0x600 mm/page-writeback.c:2634
__writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x60d/0xfa0 fs/fs-writeback.c:1976
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2047
wb_writeback+0x7f3/0xb70 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0x8ca/0xbe0 fs/fs-writeback.c:2343
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz.0.76:6653 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.76 state:D stack:28232 pid:6653 tgid:6653 ppid:6461 task_flags:0x440040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
io_schedule+0xbf/0x130 kernel/sched/core.c:7903
bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:250
__wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:67
wait_on_bit_io include/linux/wait_bit.h:105 [inline]
do_get_write_access+0x93d/0x1320 fs/jbd2/transaction.c:1092
jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
__ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:242
ext4_reserve_inode_write+0x1be/0x340 fs/ext4/inode.c:6326
__ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6501
ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6538
__mark_inode_dirty+0x1ee/0xe40 fs/fs-writeback.c:2527
generic_update_time+0xcf/0xf0 fs/inode.c:2063
inode_update_time fs/inode.c:2076 [inline]
__file_update_time fs/inode.c:2304 [inline]
file_update_time+0x17d/0x1c0 fs/inode.c:2334
ext4_page_mkwrite+0x33d/0x1880 fs/ext4/inode.c:6704
do_page_mkwrite+0x174/0x380 mm/memory.c:3361
do_shared_fault mm/memory.c:5649 [inline]
do_fault mm/memory.c:5711 [inline]
do_pte_missing+0x29d/0x3ba0 mm/memory.c:4234
handle_pte_fault mm/memory.c:6052 [inline]
__handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195
handle_mm_fault+0x589/0xd10 mm/memory.c:6364
do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fe5f3c64c9b
RSP: 002b:00007ffe16143c40 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b2f820000 RSI: 0000000000040000 RDI: 00007fe5f3e98eb0
RBP: 0000000000000000 R08: 0000000000000008 R09: 00007ffe16143986
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000022bda R15: 00007ffe16143ef0
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5c10e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5c10e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e5c10e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:6/2912:
#0: ffff8881436cd948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc9000b147d10 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
#2: ffff88803510a0e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:563
#3: ffff88803510cb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x27a/0x600 mm/page-writeback.c:2634
2 locks held by getty/5628:
#0: ffff88814d0670a0 (&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+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.0.76/6653:
#0: ffff88806411ed08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11b/0x530 mm/mmap_lock.c:147
#1: ffff88803510a520 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x174/0x380 mm/memory.c:3361
#2: ffff88803510e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
3 locks held by syz-executor/6655:
#0: ffff88803510a428 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10e/0x4a0 fs/namei.c:4132
#1: ffff8880125a59f0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:915 [inline]
#1: ffff8880125a59f0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1bb/0x4a0 fs/namei.c:4139
#2: ffff88803510e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 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 08/18/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf0e/0x1260 kernel/hung_task.c:491
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
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 08/18/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 8c 64 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 e3 d1 18 00 fb f4 7c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c6
RAX: 00000000001274ef RBX: 0000000000000000 RCX: ffffffff8b913bf9
RDX: 0000000000000000 RSI: ffffffff8de4eb89 RDI: ffffffff8c163180
RBP: fffffbfff1c52ef8 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e2977c0 R14: ffffffff90aba290 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb2d63e6e80 CR3: 000000000e380000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:757
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x391/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:744
start_kernel+0x3ee/0x4d0 init/main.c:1097
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
common_startup_64+0x13e/0x148