====================================================== WARNING: possible circular locking dependency detected 6.1.0-syzkaller-14446-g8395ae05cb5a #0 Not tainted ------------------------------------------------------ kworker/1:0/23 is trying to acquire lock: ffff88802c73ae18 (&pool->lock){-.-.}-{2:2}, at: __queue_work+0x367/0x13b0 kernel/workqueue.c:1474 but task is already holding lock: ffff888076f9a528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&tty->write_wait){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x53e/0xe00 drivers/tty/serial/8250/8250_port.c:1858 __start_tx drivers/tty/serial/8250/8250_port.c:1575 [inline] serial8250_start_tx+0x6d5/0x850 drivers/tty/serial/8250/8250_port.c:1681 __uart_start.isra.0+0x16b/0x1b0 drivers/tty/serial/serial_core.c:141 uart_write+0x2ff/0x570 drivers/tty/serial/serial_core.c:601 process_output_block drivers/tty/n_tty.c:586 [inline] n_tty_write+0x4ce/0xfd0 drivers/tty/n_tty.c:2350 do_tty_write drivers/tty/tty_io.c:1018 [inline] file_tty_write.constprop.0+0x452/0x890 drivers/tty/tty_io.c:1089 redirected_tty_write+0xa5/0xc0 drivers/tty/tty_io.c:1110 call_write_iter include/linux/fs.h:2186 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x9ed/0xdd0 fs/read_write.c:584 ksys_write+0x12b/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #3 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 serial8250_console_write+0x4ba/0x1010 drivers/tty/serial/8250/8250_port.c:3394 call_console_driver kernel/printk/printk.c:2031 [inline] console_emit_next_record.constprop.0+0x3d8/0x890 kernel/printk/printk.c:2823 console_flush_all+0x547/0x6e0 kernel/printk/printk.c:2887 console_unlock+0xb8/0x1f0 kernel/printk/printk.c:2964 vprintk_emit+0x1bd/0x600 kernel/printk/printk.c:2357 vprintk+0x84/0xa0 kernel/printk/printk_safe.c:50 _printk+0xbe/0xf1 kernel/printk/printk.c:2378 register_console+0x7e5/0xe10 kernel/printk/printk.c:3415 univ8250_console_init+0x3e/0x4a drivers/tty/serial/8250/8250_core.c:688 console_init+0x3bb/0x582 kernel/printk/printk.c:3558 start_kernel+0x2e0/0x470 init/main.c:1077 secondary_startup_64_no_verify+0xce/0xdb -> #2 (console_owner){-.-.}-{0:0}: console_lock_spinning_enable kernel/printk/printk.c:1888 [inline] console_emit_next_record.constprop.0+0x2e3/0x890 kernel/printk/printk.c:2820 console_flush_all+0x547/0x6e0 kernel/printk/printk.c:2887 console_unlock+0xb8/0x1f0 kernel/printk/printk.c:2964 vprintk_emit+0x1bd/0x600 kernel/printk/printk.c:2357 vprintk+0x84/0xa0 kernel/printk/printk_safe.c:50 _printk+0xbe/0xf1 kernel/printk/printk.c:2378 build_zonelists.cold+0xe5/0x11f mm/page_alloc.c:6497 __build_all_zonelists+0x122/0x180 mm/page_alloc.c:6610 build_all_zonelists_init+0x35/0x12f mm/page_alloc.c:6635 build_all_zonelists+0x123/0x140 mm/page_alloc.c:6668 start_kernel+0xbd/0x470 init/main.c:971 secondary_startup_64_no_verify+0xce/0xdb -> #1 (zonelist_update_seq.seqcount){...-}-{0:0}: seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline] read_seqbegin include/linux/seqlock.h:836 [inline] zonelist_iter_begin mm/page_alloc.c:4722 [inline] __alloc_pages_slowpath.constprop.0+0x1ae/0x23d0 mm/page_alloc.c:5044 __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5562 __alloc_pages_node include/linux/gfp.h:237 [inline] kmem_getpages mm/slab.c:1363 [inline] cache_grow_begin+0x94/0x390 mm/slab.c:2574 cache_alloc_refill+0x27f/0x380 mm/slab.c:2947 ____cache_alloc mm/slab.c:3023 [inline] ____cache_alloc mm/slab.c:3006 [inline] __do_cache_alloc mm/slab.c:3206 [inline] slab_alloc_node mm/slab.c:3254 [inline] slab_alloc mm/slab.c:3270 [inline] __kmem_cache_alloc_lru mm/slab.c:3447 [inline] kmem_cache_alloc+0x366/0x460 mm/slab.c:3456 kmem_cache_zalloc include/linux/slab.h:710 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:168 __debug_object_init+0x7a/0xd10 lib/debugobjects.c:569 debug_object_init lib/debugobjects.c:624 [inline] debug_object_activate+0x330/0x3e0 lib/debugobjects.c:710 debug_work_activate kernel/workqueue.c:510 [inline] __queue_work+0x682/0x13b0 kernel/workqueue.c:1516 call_timer_fn+0x1da/0x7c0 kernel/time/timer.c:1700 expire_timers+0xbb/0x5c0 kernel/time/timer.c:1746 __run_timers kernel/time/timer.c:2022 [inline] __run_timers kernel/time/timer.c:1995 [inline] run_timer_softirq+0x64c/0x910 kernel/time/timer.c:2037 __do_softirq+0x1fb/0xadc kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] default_idle+0xf/0x10 arch/x86/kernel/process.c:730 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x410/0x590 kernel/sched/idle.c:303 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:400 start_secondary+0x256/0x300 arch/x86/kernel/smpboot.c:264 secondary_startup_64_no_verify+0xce/0xdb -> #0 (&pool->lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __queue_work+0x367/0x13b0 kernel/workqueue.c:1474 queue_work_on+0xf2/0x110 kernel/workqueue.c:1545 queue_work include/linux/workqueue.h:503 [inline] schedule_work include/linux/workqueue.h:564 [inline] p9_pollwake+0xc1/0x1d0 net/9p/trans_fd.c:540 __wake_up_common+0x147/0x650 kernel/sched/wait.c:107 __wake_up_common_lock+0xd4/0x140 kernel/sched/wait.c:138 tty_write_unlock drivers/tty/tty_io.c:939 [inline] do_tty_write drivers/tty/tty_io.c:1043 [inline] file_tty_write.constprop.0+0x504/0x890 drivers/tty/tty_io.c:1089 __kernel_write_iter+0x262/0x730 fs/read_write.c:517 __kernel_write fs/read_write.c:537 [inline] kernel_write fs/read_write.c:558 [inline] kernel_write+0x1c1/0x630 fs/read_write.c:548 p9_fd_write net/9p/trans_fd.c:434 [inline] p9_write_work+0x25a/0xc60 net/9p/trans_fd.c:485 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x669/0x1090 kernel/workqueue.c:2436 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 other info that might help us debug this: Chain exists of: &pool->lock --> &port_lock_key --> &tty->write_wait Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&tty->write_wait); lock(&port_lock_key); lock(&tty->write_wait); lock(&pool->lock); *** DEADLOCK *** 5 locks held by kworker/1:0/23: #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline] #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline] #0: ffff888012469d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x86d/0x1710 kernel/workqueue.c:2260 #1: ffffc9000071fda8 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x8a1/0x1710 kernel/workqueue.c:2264 #2: ffff888076f9a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244 #3: ffff888076f9a528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 #4: ffffffff8c78e800 (rcu_read_lock){....}-{1:2}, at: __queue_work+0xca/0x13b0 kernel/workqueue.c:1437 stack backtrace: CPU: 1 PID: 23 Comm: kworker/1:0 Not tainted 6.1.0-syzkaller-14446-g8395ae05cb5a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Workqueue: events p9_write_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __queue_work+0x367/0x13b0 kernel/workqueue.c:1474 queue_work_on+0xf2/0x110 kernel/workqueue.c:1545 queue_work include/linux/workqueue.h:503 [inline] schedule_work include/linux/workqueue.h:564 [inline] p9_pollwake+0xc1/0x1d0 net/9p/trans_fd.c:540 __wake_up_common+0x147/0x650 kernel/sched/wait.c:107 __wake_up_common_lock+0xd4/0x140 kernel/sched/wait.c:138 tty_write_unlock drivers/tty/tty_io.c:939 [inline] do_tty_write drivers/tty/tty_io.c:1043 [inline] file_tty_write.constprop.0+0x504/0x890 drivers/tty/tty_io.c:1089 __kernel_write_iter+0x262/0x730 fs/read_write.c:517 __kernel_write fs/read_write.c:537 [inline] kernel_write fs/read_write.c:558 [inline] kernel_write+0x1c1/0x630 fs/read_write.c:548 p9_fd_write net/9p/trans_fd.c:434 [inline] p9_write_work+0x25a/0xc60 net/9p/trans_fd.c:485 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x669/0x1090 kernel/workqueue.c:2436 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308