RBP: 00007f6b2285f1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd37332fdf R14: 00007f6b2285f300 R15: 0000000000022000 ====================================================== WARNING: possible circular locking dependency detected 5.10.96 #1 Not tainted ------------------------------------------------------ syz-executor.3/14435 is trying to acquire lock: ffffffff84d0ac00 (console_owner){-.-.}-{0:0}, at: console_unlock+0x2e1/0xb30 kernel/printk/printk.c:2505 but task is already holding lock: ffff88803b62e158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x516/0xb40 drivers/tty/serial/8250/8250_port.c:1851 serial8250_handle_irq.part.0+0x3f1/0x4c0 drivers/tty/serial/8250/8250_port.c:1938 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1911 [inline] serial8250_default_handle_irq+0xb8/0x230 drivers/tty/serial/8250/8250_port.c:1954 serial8250_interrupt+0xf4/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x2ef/0x820 kernel/irq/handle.c:156 handle_irq_event_percpu kernel/irq/handle.c:196 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:213 handle_edge_irq+0x249/0xd00 kernel/irq/chip.c:822 asm_call_irq_on_stack+0x12/0x20 __run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline] run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [inline] handle_irq arch/x86/kernel/irq.c:230 [inline] __common_interrupt arch/x86/kernel/irq.c:249 [inline] common_interrupt+0xdd/0x190 arch/x86/kernel/irq.c:239 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:626 native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] default_idle+0xe/0x10 arch/x86/kernel/process.c:689 default_idle_call+0x87/0xd0 kernel/sched/idle.c:112 cpuidle_idle_call kernel/sched/idle.c:194 [inline] do_idle+0x3a9/0x520 kernel/sched/idle.c:300 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:396 secondary_startup_64_no_verify+0xc2/0xcb -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159 serial8250_console_write+0x8dd/0xb20 drivers/tty/serial/8250/8250_port.c:3330 call_console_drivers kernel/printk/printk.c:1909 [inline] console_unlock+0x826/0xb30 kernel/printk/printk.c:2530 register_console kernel/printk/printk.c:2871 [inline] register_console+0x53d/0x800 kernel/printk/printk.c:2761 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690 console_init+0x361/0x4fa kernel/printk/printk.c:2981 start_kernel+0x2f2/0x49b init/main.c:985 secondary_startup_64_no_verify+0xc2/0xcb -> #0 (console_owner){-.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 console_lock_spinning_enable kernel/printk/printk.c:1761 [inline] console_unlock+0x360/0xb30 kernel/printk/printk.c:2527 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2052 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2100 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x472/0x5a0 lib/fault-inject.c:146 should_failslab+0x5/0x10 mm/slab_common.c:1193 slab_pre_alloc_hook mm/slab.h:515 [inline] slab_alloc_node mm/slub.c:2821 [inline] slab_alloc mm/slub.c:2904 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3967 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 tty_put_char+0x129/0x150 drivers/tty/tty_io.c:3123 __process_echoes+0x57c/0x9f0 drivers/tty/n_tty.c:723 flush_echoes drivers/tty/n_tty.c:824 [inline] __receive_buf drivers/tty/n_tty.c:1643 [inline] n_tty_receive_buf_common+0xb85/0x2b70 drivers/tty/n_tty.c:1737 tiocsti drivers/tty/tty_io.c:2277 [inline] tty_ioctl+0x51b/0x1830 drivers/tty/tty_io.c:2658 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &port->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); *** DEADLOCK *** 6 locks held by syz-executor.3/14435: #0: ffff8880437a9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffff88803b6280b8 (&port->buf.lock/1){+.+.}-{3:3}, at: tiocsti drivers/tty/tty_io.c:2275 [inline] #1: ffff88803b6280b8 (&port->buf.lock/1){+.+.}-{3:3}, at: tty_ioctl+0x4ae/0x1830 drivers/tty/tty_io.c:2658 #2: ffff8880437a92e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: isig+0x37d/0x430 drivers/tty/n_tty.c:1147 #3: ffffc90011b0d378 (&ldata->output_lock){+.+.}-{3:3}, at: flush_echoes drivers/tty/n_tty.c:822 [inline] #3: ffffc90011b0d378 (&ldata->output_lock){+.+.}-{3:3}, at: __receive_buf drivers/tty/n_tty.c:1643 [inline] #3: ffffc90011b0d378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_receive_buf_common+0xb46/0x2b70 drivers/tty/n_tty.c:1737 #4: ffff88803b62e158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 #5: ffffffff84deaf80 (console_lock){+.+.}-{0:0}, at: vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 stack backtrace: CPU: 1 PID: 14435 Comm: syz-executor.3 Not tainted 5.10.96 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2121 check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 console_lock_spinning_enable kernel/printk/printk.c:1761 [inline] console_unlock+0x360/0xb30 kernel/printk/printk.c:2527 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2052 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2100 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x472/0x5a0 lib/fault-inject.c:146 should_failslab+0x5/0x10 mm/slab_common.c:1193 slab_pre_alloc_hook mm/slab.h:515 [inline] slab_alloc_node mm/slub.c:2821 [inline] slab_alloc mm/slub.c:2904 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3967 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 tty_put_char+0x129/0x150 drivers/tty/tty_io.c:3123 __process_echoes+0x57c/0x9f0 drivers/tty/n_tty.c:723 flush_echoes drivers/tty/n_tty.c:824 [inline] __receive_buf drivers/tty/n_tty.c:1643 [inline] n_tty_receive_buf_common+0xb85/0x2b70 drivers/tty/n_tty.c:1737 tiocsti drivers/tty/tty_io.c:2277 [inline] tty_ioctl+0x51b/0x1830 drivers/tty/tty_io.c:2658 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6b252e9b19 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6b2285f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6b253fcf60 RCX: 00007f6b252e9b19 RDX: 00000000200000c0 RSI: 0000000000005412 RDI: 0000000000000004 RBP: 00007f6b2285f1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd37332fdf R14: 00007f6b2285f300 R15: 0000000000022000