RDX: 00000000ffffff0b RSI: 0000000020c34fff RDI: 0000000000000004 RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402690 R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000 ====================================================== WARNING: possible circular locking dependency detected 4.19.34 #2 Not tainted ------------------------------------------------------ syz-executor281/7929 is trying to acquire lock: 00000000d46d5bf4 (console_owner){-...}, at: log_next kernel/printk/printk.c:497 [inline] 00000000d46d5bf4 (console_owner){-...}, at: console_unlock+0x426/0x1080 kernel/printk/printk.c:2397 but task is already holding lock: 00000000e525e911 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xff/0x200 drivers/tty/pty.c:119 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&port->lock)->rlock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 tty_port_tty_get+0x22/0x80 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x16/0x40 drivers/tty/tty_port.c:47 tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:390 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:103 serial8250_tx_chars+0x4a4/0xb20 drivers/tty/serial/8250/8250_port.c:1806 serial8250_handle_irq.part.0+0x1e2/0x270 drivers/tty/serial/8250/8250_port.c:1879 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865 [inline] serial8250_default_handle_irq+0xc5/0x150 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0x102/0x1e0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x146/0x900 kernel/irq/handle.c:149 handle_irq_event_percpu+0x74/0x160 kernel/irq/handle.c:189 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206 handle_edge_irq+0x264/0x8e0 kernel/irq/chip.c:791 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x252/0x3d8 arch/x86/kernel/irq_64.c:78 do_IRQ+0x99/0x1d0 arch/x86/kernel/irq.c:246 ret_from_intr+0x0/0x1e native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:552 default_idle_call+0x36/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x386/0x570 kernel/sched/idle.c:262 cpu_startup_entry+0xc8/0xe0 kernel/sched/idle.c:368 rest_init+0xf1/0xf6 init/main.c:442 start_kernel+0x88f/0x8c8 init/main.c:738 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&port_lock_key){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 serial8250_console_write+0x7ed/0xa10 drivers/tty/serial/8250/8250_port.c:3247 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590 call_console_drivers kernel/printk/printk.c:1729 [inline] console_unlock+0xbbe/0x1080 kernel/printk/printk.c:2410 vprintk_emit+0x238/0x690 kernel/printk/printk.c:1927 vprintk_default+0x28/0x30 kernel/printk/printk.c:1968 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2001 register_console+0x787/0xb90 kernel/printk/printk.c:2725 univ8250_console_init+0x3e/0x4b drivers/tty/serial/8250/8250_core.c:685 console_init+0x4f7/0x761 kernel/printk/printk.c:2811 start_kernel+0x59f/0x8c8 init/main.c:661 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #0 (console_owner){-...}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903 console_lock_spinning_enable kernel/printk/printk.c:1592 [inline] console_unlock+0x490/0x1080 kernel/printk/printk.c:2407 vprintk_emit+0x238/0x690 kernel/printk/printk.c:1927 vprintk_default+0x28/0x30 kernel/printk/printk.c:1968 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2001 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x6f1/0x85c lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x71/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x1fb/0x5c0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:121 n_tty_write+0xb06/0x1100 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:958 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1042 __vfs_write+0x116/0x820 fs/read_write.c:485 vfs_write+0x20c/0x560 fs/read_write.c:549 ksys_write+0xea/0x1f0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: console_owner --> &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(console_owner); *** DEADLOCK *** 6 locks held by syz-executor281/7929: #0: 00000000eec7e1a2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000e6694a86 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock+0x23/0x90 drivers/tty/tty_io.c:884 #2: 000000007c9edac7 (&tty->termios_rwsem){++++}, at: n_tty_write+0x1ab/0x1100 drivers/tty/n_tty.c:2314 #3: 000000008fd1a235 (&ldata->output_lock){+.+.}, at: n_tty_write+0xac1/0x1100 drivers/tty/n_tty.c:2353 #4: 00000000e525e911 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xff/0x200 drivers/tty/pty.c:119 #5: 00000000df78913d (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1654 [inline] #5: 00000000df78913d (console_lock){+.+.}, at: vprintk_emit+0x21d/0x690 kernel/printk/printk.c:1926 stack backtrace: CPU: 1 PID: 7929 Comm: syz-executor281 Not tainted 4.19.34 #2 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+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f 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+0x2e6d/0x48f0 kernel/locking/lockdep.c:3411 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903 console_lock_spinning_enable kernel/printk/printk.c:1592 [inline] console_unlock+0x490/0x1080 kernel/printk/printk.c:2407 vprintk_emit+0x238/0x690 kernel/printk/printk.c:1927 vprintk_default+0x28/0x30 kernel/printk/printk.c:1968 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2001 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x6f1/0x85c lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x71/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x1fb/0x5c0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:121 n_tty_write+0xb06/0x1100 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:958 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1042 __vfs_write+0x116/0x820 fs/read_write.c:485 vfs_write+0x20c/0x560 fs/read_write.c:549 ksys_write+0xea/0x1f0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441769 Code: e8 cc ac 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 9b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc07534fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ffc07534ff0 RCX: 0000000000441769 RDX: 00000000ffffff0b RSI: 0000000020c34fff RDI: 0000000000000004 RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402690 R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 7930 Comm: syz-executor281 Not tainted 4.19.34 #2 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+0x172/0x1f0 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0xa/0x1b lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x71/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x1fb/0x5c0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:121 n_tty_write+0xb06/0x1100 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:958 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1042 __vfs_write+0x116/0x820 fs/read_write.c:485 vfs_write+0x20c/0x560 fs/read_write.c:549 ksys_write+0xea/0x1f0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441769 Code: e8 cc ac 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 9b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc07534fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ffc07534ff0 RCX: 0000000000441769 RDX: 00000000ffffff0b RSI: 0000000020c34fff RDI: 0000000000000004 RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402690 R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 7931 Comm: syz-executor281 Not tainted 4.19.34 #2 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+0x172/0x1f0 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0xa/0x1b lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x71/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x1fb/0x5c0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:121 n_tty_write+0xb06/0x1100 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:958 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1042 __vfs_write+0x116/0x820 fs/read_write.c:485 vfs_write+0x20c/0x560 fs/read_write.c:549 ksys_write+0xea/0x1f0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441769 Code: e8 cc ac 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 9b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc07534fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ffc07534ff0 RCX: 0000000000441769 RDX: 00000000ffffff0b RSI: 0000000020c34fff RDI: 0000000000000004 RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402690 R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000