====================================================== WARNING: possible circular locking dependency detected 4.19.134-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/10986 is trying to acquire lock: 0000000006773c6e (&pool->lock/1){..-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 0000000006773c6e (&pool->lock/1){..-.}, at: __queue_work+0x359/0x1100 kernel/workqueue.c:1419 but task is already holding lock: 000000003313448e (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf6/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&(&port->lock)->rlock){-.-.}: tty_port_tty_get+0x1d/0x80 drivers/tty/tty_port.c:289 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1806 serial8250_handle_irq.part.0+0x24b/0x290 drivers/tty/serial/8250/8250_port.c:1879 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865 [inline] serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0xf2/0x1d0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu kernel/irq/handle.c:189 [inline] handle_irq_event+0x102/0x285 kernel/irq/handle.c:206 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:797 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246 ret_from_intr+0x0/0x1e native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x49/0x310 arch/x86/kernel/process.c:557 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263 cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369 start_secondary+0x41f/0x580 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #3 (&port_lock_key){-.-.}: serial8250_console_write+0x89b/0xad0 drivers/tty/serial/8250/8250_port.c:3253 call_console_drivers kernel/printk/printk.c:1764 [inline] console_unlock+0xbb6/0x1110 kernel/printk/printk.c:2457 vprintk_emit+0x2d1/0x740 kernel/printk/printk.c:1965 vprintk_func+0x79/0x17e kernel/printk/printk_safe.c:397 printk+0xba/0xed kernel/printk/printk.c:2040 register_console+0x87f/0xc90 kernel/printk/printk.c:2773 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:684 console_init+0x4cb/0x718 kernel/printk/printk.c:2859 start_kernel+0x686/0x911 init/main.c:659 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #2 (console_owner){-...}: vprintk_func+0x79/0x17e kernel/printk/printk_safe.c:397 printk+0xba/0xed kernel/printk/printk.c:2040 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x66b/0x7b0 lib/fault-inject.c:149 __should_failslab+0x115/0x180 mm/failslab.c:32 should_failslab+0x5/0xf mm/slab_common.c:1558 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] kmem_cache_alloc+0x3f/0x370 mm/slab.c:3557 kmem_cache_zalloc include/linux/slab.h:699 [inline] fill_pool lib/debugobjects.c:134 [inline] __debug_object_init+0x6d9/0x9b0 lib/debugobjects.c:379 __init_work kernel/workqueue.c:502 [inline] insert_wq_barrier kernel/workqueue.c:2546 [inline] start_flush_work kernel/workqueue.c:2888 [inline] __flush_work+0x270/0x8b0 kernel/workqueue.c:2927 __cancel_work_timer+0x412/0x590 kernel/workqueue.c:3015 uhid_dev_destroy drivers/hid/uhid.c:568 [inline] uhid_char_release+0xa7/0x190 drivers/hid/uhid.c:645 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 get_signal+0x1b64/0x1f70 kernel/signal.c:2399 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&(&pool->lock)->rlock){-.-.}: spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x359/0x1100 kernel/workqueue.c:1419 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1488 queue_work include/linux/workqueue.h:512 [inline] schedule_work include/linux/workqueue.h:570 [inline] put_pwq+0x15a/0x1b0 kernel/workqueue.c:1090 put_pwq_unlocked kernel/workqueue.c:1107 [inline] put_pwq_unlocked kernel/workqueue.c:1099 [inline] destroy_workqueue+0x649/0x790 kernel/workqueue.c:4243 do_floppy_init drivers/block/floppy.c:4737 [inline] floppy_async_init+0x1eeb/0x2024 drivers/block/floppy.c:4754 async_run_entry_fn+0x121/0x530 kernel/async.c:127 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x30b/0x410 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #0 (&pool->lock/1){..-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x359/0x1100 kernel/workqueue.c:1419 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1488 pty_write+0x198/0x1f0 drivers/tty/pty.c:125 n_tty_write+0xa03/0xff0 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x496/0x810 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x770 fs/read_write.c:485 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &pool->lock/1 --> &port_lock_key --> &(&port->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&port->lock)->rlock); lock(&port_lock_key); lock(&(&port->lock)->rlock); lock(&pool->lock/1); *** DEADLOCK *** 5 locks held by syz-executor.0/10986: #0: 000000003dbb024e (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000b28dc8d7 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock drivers/tty/tty_io.c:886 [inline] #1: 00000000b28dc8d7 (&tty->atomic_write_lock){+.+.}, at: do_tty_write drivers/tty/tty_io.c:909 [inline] #1: 00000000b28dc8d7 (&tty->atomic_write_lock){+.+.}, at: tty_write+0x24e/0x810 drivers/tty/tty_io.c:1044 #2: 00000000ff26fa68 (&tty->termios_rwsem){++++}, at: n_tty_write+0x1b5/0xff0 drivers/tty/n_tty.c:2314 #3: 00000000a066735e (&ldata->output_lock){+.+.}, at: n_tty_write+0x9d0/0xff0 drivers/tty/n_tty.c:2353 #4: 000000003313448e (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf6/0x1f0 drivers/tty/pty.c:120 stack backtrace: CPU: 1 PID: 10986 Comm: syz-executor.0 Not tainted 4.19.134-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2fe lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3415 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x359/0x1100 kernel/workqueue.c:1419 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1488 pty_write+0x198/0x1f0 drivers/tty/pty.c:125 n_tty_write+0xa03/0xff0 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x496/0x810 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x770 fs/read_write.c:485 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c369 Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007feb6c2b6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000037280 RCX: 000000000045c369 RDX: 0000000000000041 RSI: 0000000020001140 RDI: 0000000000000003 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc0cd00c3f R14: 00007feb6c2b79c0 R15: 000000000078bf0c