INFO: task kworker/u8:6:1321 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:1321  tgid:1321  ppid:2      task_flags:0x4248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 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
 </TASK>
INFO: task syz.0.243:6946 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.243       state:D stack:28568 pid:6946  tgid:6946  ppid:6382   task_flags:0x440040 flags:0x00004004
Call Trace:
 <TASK>
 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: 0033:0x7fa85ec6547b
RSP: 002b:00007fff4667fc90 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b32820000 RSI: 0000000000040000 RDI: 00007fa85ee98d50
RBP: 0000000000000000 R08: 0000000000000009 R09: 00007fff4667f9d5
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000240ee R15: 00007fff4667ff40
 </TASK>

Showing all locks held in the system:
1 lock held by ksoftirqd/0/15:
 #0: ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:636
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/u8:6/1321:
 #0: ffff88801eaa5948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
 #1: ffffc9000486fd10 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
 #2: ffff888035bcc0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:563
 #3: ffff888035bceb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x27a/0x600 mm/page-writeback.c:2634
2 locks held by getty/5627:
 #0: ffff88814d3040a0 (&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.0.243/6946:
 #0: ffff88807fe2ad08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11b/0x530 mm/mmap_lock.c:147
 #1: ffff888035bcc520 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x174/0x380 mm/memory.c:3361
 #2: ffff888035bd0950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
3 locks held by syz-executor/6947:
 #0: ffff888035bcc428 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10e/0x4a0 fs/namei.c:4132
 #1: ffff888012d233b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:915 [inline]
 #1: ffff888012d233b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1bb/0x4a0 fs/namei.c:4139
 #2: ffff888035bd0950 (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:
 <TASK>
 __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
 </TASK>
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:do_raw_spin_lock+0x50/0x2b0 kernel/locking/spinlock_debug.c:114
Code: b3 8a b5 41 48 8d 6c 24 08 48 c7 44 24 10 fd 35 e2 8d 48 c1 ed 03 48 c7 44 24 18 90 ab 97 81 48 8d 54 05 00 c7 02 f1 f1 f1 f1 <c7> 42 04 04 f3 f3 f3 65 48 8b 15 19 84 3e 12 48 89 54 24 60 31 d2
RSP: 0018:ffffc90000007a18 EFLAGS: 00000806
RAX: dffffc0000000000 RBX: ffff8880b85288a8 RCX: ffffffff93dd89e0
RDX: fffff52000000f44 RSI: ffffffff8de296dd RDI: ffff8880b85288ac
RBP: 1ffff92000000f44 R08: aefbc0360f6c0f7d R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000001 R14: ffff8880b85288a8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b33bc95ed0 CR3: 000000000e380000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162
 cpu_stop_queue_work+0x6b/0x340 kernel/stop_machine.c:98
 sched_balance_rq+0x2128/0x3110 kernel/sched/fair.c:11852
 sched_balance_domains+0x6ff/0xee0 kernel/sched/fair.c:12141
 _nohz_idle_balance.isra.0+0x5fc/0x840 kernel/sched/fair.c:12576
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0xa4/0xc0 arch/x86/kernel/smp.c:266
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
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 <e9> 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: 000000000013d85b 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
 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
 </TASK>