====================================================== WARNING: possible circular locking dependency detected 5.10.123 #1 Not tainted ------------------------------------------------------ syz-executor.0/21899 is trying to acquire lock: ffff888048281578 (&tty->read_wait){....}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff888048281578 (&tty->read_wait){....}-{2:2}, at: io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5051 but task is already holding lock: ffff888048281528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 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+0x36/0x50 kernel/locking/spinlock.c:159 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50 serial8250_tx_chars+0x516/0xa90 drivers/tty/serial/8250/8250_port.c:1861 serial8250_handle_irq.part.0+0x3f1/0x4c0 drivers/tty/serial/8250/8250_port.c:1948 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1921 [inline] serial8250_default_handle_irq+0xb8/0x230 drivers/tty/serial/8250/8250_port.c:1964 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+0xff/0x280 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_restore_fl arch/x86/include/asm/irqflags.h:41 [inline] arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x25/0x40 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline] uart_write+0x304/0x580 drivers/tty/serial/serial_core.c:622 do_output_char+0x5e4/0x860 drivers/tty/n_tty.c:442 process_output drivers/tty/n_tty.c:509 [inline] n_tty_write+0x487/0xf90 drivers/tty/n_tty.c:2395 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x4f8/0x8d0 drivers/tty/tty_io.c:1118 redirected_tty_write+0xa1/0xc0 drivers/tty/tty_io.c:1125 call_write_iter include/linux/fs.h:1903 [inline] do_iter_readv_writev+0x476/0x750 fs/read_write.c:740 do_iter_write+0x18d/0x670 fs/read_write.c:866 vfs_writev+0x1aa/0x5e0 fs/read_write.c:939 do_writev+0x139/0x300 fs/read_write.c:982 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&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+0x90b/0xb60 drivers/tty/serial/8250/8250_port.c:3340 FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 call_console_drivers kernel/printk/printk.c:1911 [inline] console_unlock+0x826/0xb30 kernel/printk/printk.c:2532 register_console kernel/printk/printk.c:2873 [inline] register_console+0x53d/0x800 kernel/printk/printk.c:2763 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690 console_init+0x361/0x4fa kernel/printk/printk.c:2983 CPU: 0 PID: 21905 Comm: syz-executor.1 Not tainted 5.10.123 #1 start_kernel+0x2e1/0x48a init/main.c:982 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 secondary_startup_64_no_verify+0xc2/0xcb -> #2 Call Trace: ( __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 console_owner){-.-.}-{0:0} fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 : _copy_to_user+0x2e/0x180 lib/usercopy.c:29 console_lock_spinning_enable kernel/printk/printk.c:1763 [inline] console_unlock+0x360/0xb30 kernel/printk/printk.c:2529 copy_to_user include/linux/uaccess.h:200 [inline] simple_read_from_buffer+0xcc/0x160 fs/libfs.c:729 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2054 proc_fail_nth_read+0x194/0x220 fs/proc/base.c:1423 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2102 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] kmem_cache_alloc+0x5b/0x350 mm/slub.c:2909 vfs_read+0x228/0x580 fs/read_write.c:494 __sigqueue_alloc+0x1ee/0x560 kernel/signal.c:435 __send_signal+0x5db/0x1040 kernel/signal.c:1116 ksys_read+0x12d/0x250 fs/read_write.c:634 do_send_sig_info kernel/signal.c:1291 [inline] send_sig_info kernel/signal.c:1606 [inline] send_sig+0xcb/0x160 kernel/signal.c:1616 sk_stream_error+0xaa/0x100 net/core/stream.c:188 tcp_sendmsg_locked+0x1633/0x2f10 net/ipv4/tcp.c:1432 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1447 entry_SYSCALL_64_after_hwframe+0x44/0xa9 inet6_sendmsg+0xb5/0x140 net/ipv6/af_inet6.c:638 RIP: 0033:0x7f88a9f4269c sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xee/0x190 net/socket.c:671 ____sys_sendmsg+0x709/0x870 net/socket.c:2342 Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 fc ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 2f fd ff ff 48 ___sys_sendmsg+0xf3/0x170 net/socket.c:2396 RSP: 002b:00007f88a74e4170 EFLAGS: 00000246 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2429 ORIG_RAX: 0000000000000000 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00007f88a9f4269c entry_SYSCALL_64_after_hwframe+0x44/0xa9 RDX: 000000000000000f RSI: 00007f88a74e41e0 RDI: 0000000000000004 -> #1 RBP: 00007f88a74e41d0 R08: 0000000000000000 R09: 0000000000000000 ( R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffdb2e978df R14: 00007f88a74e4300 R15: 0000000000022000 &sighand->siglock hpet: Lost 3 RTC interrupts ){-.-.}-{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 __lock_task_sighand+0xd3/0x2f0 kernel/signal.c:1391 lock_task_sighand include/linux/sched/signal.h:693 [inline] task_work_add+0x1db/0x2b0 kernel/task_work.c:58 io_req_task_work_add fs/io_uring.c:2062 [inline] __io_async_wake+0x40b/0x8d0 fs/io_uring.c:4938 __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123 tty_ldisc_lock+0x40/0xb0 drivers/tty/tty_ldisc.c:335 tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744 __tty_hangup.part.0+0x510/0x9b0 drivers/tty/tty_io.c:624 __tty_hangup drivers/tty/tty_io.c:574 [inline] tty_vhangup drivers/tty/tty_io.c:697 [inline] tty_ioctl+0x120e/0x1830 drivers/tty/tty_io.c:2683 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 -> #0 (&tty->read_wait){....}-{2:2}: check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain kernel/locking/lockdep.c:3728 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4954 lock_acquire kernel/locking/lockdep.c:5564 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5529 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x27/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5051 __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123 tty_ldisc_lock+0x55/0xb0 drivers/tty/tty_ldisc.c:336 tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744 __tty_hangup.part.0+0x510/0x9b0 drivers/tty/tty_io.c:624 __tty_hangup drivers/tty/tty_io.c:574 [inline] tty_vhangup drivers/tty/tty_io.c:697 [inline] tty_ioctl+0x120e/0x1830 drivers/tty/tty_io.c:2683 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: &tty->read_wait --> &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(&tty->read_wait); *** DEADLOCK *** 2 locks held by syz-executor.0/21899: #0: ffff8880482811c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19 #1: ffff888048281528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 stack backtrace: CPU: 1 PID: 21899 Comm: syz-executor.0 Not tainted 5.10.123 #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:2123 check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain kernel/locking/lockdep.c:3728 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4954 lock_acquire kernel/locking/lockdep.c:5564 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5529 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x27/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5051 __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123 tty_ldisc_lock+0x55/0xb0 drivers/tty/tty_ldisc.c:336 tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744 __tty_hangup.part.0+0x510/0x9b0 drivers/tty/tty_io.c:624 __tty_hangup drivers/tty/tty_io.c:574 [inline] tty_vhangup drivers/tty/tty_io.c:697 [inline] tty_ioctl+0x120e/0x1830 drivers/tty/tty_io.c:2683 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: 0033:0x7fe8b2656b19 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:00007fe8afbcc188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe8b2769f60 RCX: 00007fe8b2656b19 RDX: 0000000000000000 RSI: 0000000000005437 RDI: 0000000000000004 RBP: 00007fe8b26b0f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd69d46b1f R14: 00007fe8afbcc300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: ec in (%dx),%al 1: 28 48 89 sub %cl,-0x77(%rax) 4: 54 push %rsp 5: 24 18 and $0x18,%al 7: 48 89 74 24 10 mov %rsi,0x10(%rsp) c: 89 7c 24 08 mov %edi,0x8(%rsp) 10: e8 f9 fc ff ff callq 0xfffffd0e 15: 48 8b 54 24 18 mov 0x18(%rsp),%rdx 1a: 48 8b 74 24 10 mov 0x10(%rsp),%rsi 1f: 41 89 c0 mov %eax,%r8d 22: 8b 7c 24 08 mov 0x8(%rsp),%edi 26: 31 c0 xor %eax,%eax 28: 0f 05 syscall * 2a: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax <-- trapping instruction 30: 77 34 ja 0x66 32: 44 89 c7 mov %r8d,%edi 35: 48 89 44 24 08 mov %rax,0x8(%rsp) 3a: e8 2f fd ff ff callq 0xfffffd6e 3f: 48 rex.W