audit: type=1400 audit(1583685577.864:36): avc: denied { map } for pid=8116 comm="syz-executor864" path="/root/syz-executor864187192" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 hrtimer: interrupt took 51023 ns BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 166s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: vmstat_shepherd, cache_reap, check_corruption ====================================================== WARNING: possible circular locking dependency detected 4.19.108-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor864/8116 is trying to acquire lock: 00000000fc3be13e (console_owner){-.-.}, at: log_next kernel/printk/printk.c:499 [inline] 00000000fc3be13e (console_owner){-.-.}, at: console_unlock+0x3f4/0xfe0 kernel/printk/printk.c:2416 but task is already holding lock: 00000000a1d6a799 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x7f9/0x1059 kernel/workqueue.c:4582 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&(&pool->lock)->rlock){-.-.}: spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x23c/0x1070 kernel/workqueue.c:1417 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1486 queue_work include/linux/workqueue.h:512 [inline] schedule_work include/linux/workqueue.h:570 [inline] put_pwq kernel/workqueue.c:1090 [inline] put_pwq+0x15a/0x1b0 kernel/workqueue.c:1075 put_pwq_unlocked.part.0+0x30/0x70 kernel/workqueue.c:1107 put_pwq_unlocked kernel/workqueue.c:1101 [inline] destroy_workqueue+0x5f4/0x6f0 kernel/workqueue.c:4241 do_floppy_init drivers/block/floppy.c:4737 [inline] floppy_async_init+0x1f0a/0x2043 drivers/block/floppy.c:4754 async_run_entry_fn+0x121/0x530 kernel/async.c:127 process_one_work+0x91f/0x1640 kernel/workqueue.c:2153 worker_thread+0x96/0xe20 kernel/workqueue.c:2296 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #3 (&pool->lock/1){..-.}: spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x23c/0x1070 kernel/workqueue.c:1417 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1486 pty_write+0x198/0x1f0 drivers/tty/pty.c:125 n_tty_write+0xa69/0x1080 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x452/0x790 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x760 fs/read_write.c:485 vfs_write+0x206/0x550 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 -> #2 (&(&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+0x48f/0xae0 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+0xb5/0x140 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0xf2/0x1d0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x144/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu+0x76/0x160 kernel/irq/handle.c:189 handle_irq_event+0xa2/0x12d kernel/irq/handle.c:206 handle_edge_irq+0x24b/0x8c0 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+0x49/0x320 arch/x86/kernel/process.c:565 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x2ee/0x4b0 kernel/sched/idle.c:263 cpu_startup_entry+0xc6/0xd0 kernel/sched/idle.c:369 start_secondary+0x3e4/0x590 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&port_lock_key){-.-.}: serial8250_console_write+0x79f/0x9c0 drivers/tty/serial/8250/8250_port.c:3251 call_console_drivers kernel/printk/printk.c:1736 [inline] console_unlock+0xb26/0xfe0 kernel/printk/printk.c:2429 vprintk_emit+0x282/0x6e0 kernel/printk/printk.c:1937 vprintk_func+0x79/0x17e kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2012 register_console+0x752/0xb50 kernel/printk/printk.c:2745 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:684 console_init+0x4cb/0x718 kernel/printk/printk.c:2831 start_kernel+0x594/0x81c init/main.c:660 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #0 (console_owner){-.-.}: console_lock_spinning_enable kernel/printk/printk.c:1599 [inline] console_unlock+0x45c/0xfe0 kernel/printk/printk.c:2426 vprintk_emit+0x282/0x6e0 kernel/printk/printk.c:1937 vprintk_func+0x79/0x17e kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2012 show_pwq kernel/workqueue.c:4488 [inline] show_workqueue_state.cold+0x94a/0x1059 kernel/workqueue.c:4584 wq_watchdog_timer_fn+0x4d8/0x550 kernel/workqueue.c:5596 call_timer_fn+0x177/0x700 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] __run_timers kernel/time/timer.c:1652 [inline] run_timer_softirq+0xc08/0x1540 kernel/time/timer.c:1699 __do_softirq+0x26c/0x93c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17b/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:544 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 arch_local_irq_enable arch/x86/include/asm/paravirt.h:799 [inline] __do_page_fault+0x6e3/0xdd0 arch/x86/mm/fault.c:1288 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1204 other info that might help us debug this: Chain exists of: console_owner --> &pool->lock/1 --> &(&pool->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&pool->lock)->rlock); lock(&pool->lock/1); lock(&(&pool->lock)->rlock); lock(console_owner); *** DEADLOCK *** 4 locks held by syz-executor864/8116: #0: 000000007b79f146 ((&wq_watchdog_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] #0: 000000007b79f146 ((&wq_watchdog_timer)){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1316 #1: 0000000090609218 (rcu_read_lock_sched){....}, at: show_workqueue_state+0x0/0x120 kernel/workqueue.c:4453 #2: 00000000a1d6a799 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x7f9/0x1059 kernel/workqueue.c:4582 #3: 00000000eaaeb514 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1661 [inline] #3: 00000000eaaeb514 (console_lock){+.+.}, at: vprintk_emit+0x269/0x6e0 kernel/printk/printk.c:1936 stack backtrace: CPU: 0 PID: 8116 Comm: syz-executor864 Not tainted 4.19.108-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+0x188/0x20d lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1861 [inline] check_prevs_add kernel/locking/lockdep.c:1974 [inline] validate_chain kernel/locking/lockdep.c:2415 [inline] __lock_acquire+0x2e19/0x49c0 kernel/locking/lockdep.c:3411 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3903 console_lock_spinning_enable kernel/printk/printk.c:1599 [inline] console_unlock+0x45c/0xfe0 kernel/printk/printk.c:2426 vprintk_emit+0x282/0x6e0 kernel/printk/printk.c:1937 vprintk_func+0x79/0x17e kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2012 show_pwq kernel/workqueue.c:4488 [inline] show_workqueue_state.cold+0x94a/0x1059 kernel/workqueue.c:4584 wq_watchdog_timer_fn+0x4d8/0x550 kernel/workqueue.c:5596 call_timer_fn+0x177/0x700 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] __run_timers kernel/time/timer.c:1652 [inline] run_timer_softirq+0xc08/0x1540 kernel/time/timer.c:1699 __do_softirq+0x26c/0x93c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17b/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:544 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:__do_page_fault+0x6e3/0xdd0 arch/x86/mm/fault.c:1289 Code: ff df 48 c1 e8 03 80 3c 10 00 0f 85 50 06 00 00 48 83 3d 97 89 83 07 00 0f 84 df 05 00 00 e8 c4 d5 38 00 fb 66 0f 1f 44 00 00 <49> 83 cd 04 c7 44 24 14 54 00 00 00 e9 2c fc ff ff e8 a7 d5 38 00 RSP: 0000:ffff8880898dfe78 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff88809fff8640 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff812ecd0c RDI: ffff88809fff8ebc RBP: ffff8880898dff58 R08: ffff88809fff8640 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000025c6e528 R13: 0000000000000004 R14: ffff88809ffcadc0 R15: 0000000000000000 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1204 RIP: 0033:0x401ec6 Code: 00 00 00 be fb 68 4a 00 e8 87 e4 ff ff 48 85 c0 0f 85 cb fe ff ff e9 4a ff ff ff e8 c4 68 04 00 48 6b 44 24 28 18 8b 7c 24 38 <48> 8b 88 90 01 00 20 48 8b 90 88 01 00 20 48 8b b0 80 01 00 20 e8 RSP: 002b:00007fff8a2c1c30 EFLAGS: 00010202 RAX: 0000000005c6e398 RBX: 00007fff8a2c1e00 RCX: 0000000000402023 RDX: 903b0da42fadbc53 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00007fff8a2c1c30 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000403220 R13: 00000000004032b0 R14: 0000000000000000 R15: 0000000000000000 workqueue events_power_efficient: flags=0x80 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256 refcnt=3 pending: neigh_periodic_work, check_lifetime workqueue mm_percpu_wq: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue krxrpcd: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1 refcnt=2 pending: rxrpc_peer_keepalive_worker