INFO: task syz.5.303:7228 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.303 state:D stack:24488 pid:7228 tgid:7191 ppid:5828 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 f2fs_down_write fs/f2fs/f2fs.h:2313 [inline] f2fs_issue_checkpoint+0x38a/0x5b0 fs/f2fs/checkpoint.c:1893 f2fs_do_sync_file+0x9b7/0x1810 fs/f2fs/file.c:352 generic_write_sync include/linux/fs.h:2616 [inline] f2fs_file_write_iter+0x76d/0x24a0 fs/f2fs/file.c:5270 do_iter_readv_writev+0x623/0x8c0 fs/read_write.c:-1 vfs_writev+0x31a/0x960 fs/read_write.c:1057 do_pwritev fs/read_write.c:1153 [inline] __do_sys_pwritev2 fs/read_write.c:1211 [inline] __se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7bfcf8f749 RSP: 002b:00007f7bfde22038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007f7bfd1e6090 RCX: 00007f7bfcf8f749 RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000005 RBP: 00007f7bfd013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000e7b R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7bfd1e6128 R14: 00007f7bfd1e6090 R15: 00007ffd90e3d1a8 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8df41a20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df41a20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df41a20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:8/1110: #0: ffff888140ab0148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888140ab0148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90003f9fb80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90003f9fb80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffff888052c260e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888028e29510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline] #3: ffff888028e29510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x38a/0x5b0 fs/f2fs/checkpoint.c:1893 1 lock held by klogd/5186: #0: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 2 locks held by getty/5582: #0: ffff8880340f50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 4 locks held by syz.5.303/7192: 2 locks held by syz.5.303/7228: #0: ffff888052c26420 (sb_writers#25){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff888052c26420 (sb_writers#25){.+.+}-{0:0}, at: vfs_writev+0x288/0x960 fs/read_write.c:1055 #1: ffff888028e29510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline] #1: ffff888028e29510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x38a/0x5b0 fs/f2fs/checkpoint.c:1893 2 locks held by kworker/u8:25/8358: #0: ffff88801c721948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801c721948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9001ee0fb80 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9001ee0fb80 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 2 locks held by syz.4.976/9468: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [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:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 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: 8053 Comm: kworker/0:10 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: usb_hub_wq hub_event RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline] RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x35/0x50 kernel/locking/spinlock.c:202 Code: 18 48 8b 74 24 08 e8 fa 46 40 f6 48 89 df e8 32 be 40 f6 e8 7d 29 6b f6 fb bf 01 00 00 00 e8 b2 ad 32 f6 65 8b 05 4b 50 20 07 <85> c0 74 07 5b e9 1c e1 b1 f5 cc e8 db 17 d5 f5 5b e9 10 e1 b1 f5 RSP: 0018:ffffc90000007c90 EFLAGS: 00000213 RAX: 0000000000000101 RBX: ffff8880b86260c0 RCX: 0000000000000100 RDX: 0000000000000002 RSI: ffffffff8d79261c RDI: 00000000ffffffff RBP: ffffc90000007e10 R08: ffffffff8f822077 R09: 1ffffffff1f0440e R10: dffffc0000000000 R11: fffffbfff1f0440f R12: ffff8880b86260c0 R13: 1ffff92000000fad R14: ffff888026ad8de8 R15: ffffc90000007d68 FS: 0000000000000000(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8bc2db7198 CR3: 0000000075f74000 CR4: 0000000000350ef0 Call Trace: expire_timers kernel/time/timer.c:1798 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x60a/0x860 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404 handle_softirqs+0x27d/0x850 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2037 [inline] RIP: 0010:vprintk_emit+0x4d0/0x5f0 kernel/printk/printk.c:2425 Code: 0f 84 34 ff ff ff e8 cf 62 20 00 fb eb 44 e8 c7 62 20 00 e8 82 72 ba 09 4d 85 f6 74 94 e8 b8 62 20 00 fb 48 c7 c7 e0 58 f3 8d <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 28 26 RSP: 0018:ffffc9000b897280 EFLAGS: 00000287 RAX: ffffffff81a14f98 RBX: ffffffff81a14df1 RCX: 0000000000100000 RDX: ffffc9001baef000 RSI: 0000000000008835 RDI: ffffffff8df358e0 RBP: ffffc9000b897390 R08: ffffffff8f822077 R09: 1ffffffff1f0440e R10: dffffc0000000000 R11: fffffbfff1f0440f R12: 0000000000000000 R13: 0000000000000029 R14: 0000000000000200 R15: 1ffff92001712e54 dev_vprintk_emit+0x337/0x3f0 drivers/base/core.c:4914 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4925 _dev_info+0x10a/0x160 drivers/base/core.c:4983 usb_disconnect+0xdd/0x990 drivers/usb/core/hub.c:2327 hub_port_connect drivers/usb/core/hub.c:5407 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x1ca9/0x4ef0 drivers/usb/core/hub.c:5953 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246