INFO: task syz.6.3886:11481 blocked for more than 122 seconds. Not tainted 6.12.38-syzkaller-gc46482c03ae9 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.3886 state:D stack:0 pid:11481 tgid:11480 ppid:8136 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5945 [inline] __schedule+0x1322/0x1df0 kernel/sched/core.c:7791 __schedule_loop kernel/sched/core.c:7872 [inline] schedule+0xc6/0x240 kernel/sched/core.c:7887 super_lock+0x150/0x300 fs/super.c:115 super_lock_shared fs/super.c:140 [inline] iterate_supers+0x8a/0x560 fs/super.c:934 quota_sync_all fs/quota/quota.c:69 [inline] __do_sys_quotactl fs/quota/quota.c:938 [inline] __se_sys_quotactl+0x308/0x7d0 fs/quota/quota.c:917 __x64_sys_quotactl+0x9f/0xc0 fs/quota/quota.c:917 x64_sys_call+0x2818/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:180 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f887158ebe9 RSP: 002b:00007f88723ba038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3 RAX: ffffffffffffffda RBX: 00007f88717b5fa0 RCX: 00007f887158ebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000102 RBP: 00007f8871611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f88717b6038 R14: 00007f88717b5fa0 R15: 00007ffd34e12e58 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-gc46482c03ae9 #0 80b02ff89b1607ee1d115e0157270f38c0251e02 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120 dump_stack+0x19/0x20 lib/dump_stack.c:129 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline] watchdog+0xd8f/0xed0 kernel/hung_task.c:423 kthread+0x2ca/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 611 Comm: kworker/1:4 Not tainted 6.12.38-syzkaller-gc46482c03ae9 #0 80b02ff89b1607ee1d115e0157270f38c0251e02 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_out+0x85/0xd0 drivers/tty/serial/8250/8250_port.c:413 Code: fe 44 89 e1 41 d3 e6 49 83 c7 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 54 d3 c3 fe 45 03 37 89 d8 44 89 f2 ee <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 e1 80 e1 07 RSP: 0018:ffffc9000d366fc8 EFLAGS: 00000002 RAX: 000000000000005b RBX: 000000000000005b RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000027154 RDI: 0000000000027155 RBP: ffffc9000d366ff0 R08: ffff888107aa0107 R09: 1ffff11020f54020 R10: 0000000000000000 R11: ffffffff831830e0 R12: 0000000000000000 R13: dffffc0000000000 R14: 00000000000003f8 R15: ffffffff889ecde8 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5421990f98 CR3: 0000000138aa6000 CR4: 00000000003526b0 DR0: 000000000000a7d0 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x166d/0x2130 drivers/tty/serial/8250/8250_port.c:3422 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396 console_emit_next_record kernel/printk/printk.c:3150 [inline] console_flush_all+0x5e6/0xaa0 kernel/printk/printk.c:3238 __console_flush_and_unlock kernel/printk/printk.c:3297 [inline] console_unlock+0xe9/0x270 kernel/printk/printk.c:3337 vprintk_emit+0x27c/0x640 kernel/printk/printk.c:2461 dev_vprintk_emit+0x33b/0x400 drivers/base/core.c:4962 dev_printk_emit+0xe1/0x130 drivers/base/core.c:4973 __dev_printk+0x17f/0x1b0 drivers/base/core.c:4985 _dev_info+0x10b/0x160 drivers/base/core.c:5031 announce_device+0x11d/0x2c0 drivers/usb/core/hub.c:2380 usb_new_device+0x4ce/0x1590 drivers/usb/core/hub.c:2643 hub_port_connect drivers/usb/core/hub.c:5533 [inline] hub_port_connect_change drivers/usb/core/hub.c:5673 [inline] port_event drivers/usb/core/hub.c:5837 [inline] hub_event+0x2c81/0x4270 drivers/usb/core/hub.c:5919 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400 kthread+0x2ca/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244