============================================ WARNING: possible recursive locking detected 5.16.0-rc1-syzkaller #0 Not tainted -------------------------------------------- syz-executor.4/30945 is trying to acquire lock: ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577 but task is already holding lock: ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by syz-executor.4/30945: #0: ffffffff8c359b78 (tomoyo_ss){....}-{0:0}, at: tomoyo_check_open_permission+0xe8/0x380 security/tomoyo/file.c:761 #1: ffff88807f20f530 (&i->lock){-.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #1: ffff88807f20f530 (&i->lock){-.-.}-{2:2}, at: serial8250_interrupt+0x3a/0x200 drivers/tty/serial/8250/8250_core.c:116 #2: ffffffff9078b430 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908 #3: ffff8880713aa098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273 stack backtrace: CPU: 1 PID: 30945 Comm: syz-executor.4 Not tainted 5.16.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577 n_hdlc_send_frames+0x24b/0x490 drivers/tty/n_hdlc.c:290 tty_wakeup+0xe1/0x120 drivers/tty/tty_io.c:534 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:51 serial8250_tx_chars+0x4f3/0xad0 drivers/tty/serial/8250/8250_port.c:1845 serial8250_handle_irq.part.0+0x328/0x3d0 drivers/tty/serial/8250/8250_port.c:1932 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1905 [inline] serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x303/0x8f0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:198 [inline] handle_irq_event+0x102/0x280 kernel/irq/handle.c:215 handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:822 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250 common_interrupt+0xa4/0xc0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 RIP: 0010:__sanitizer_cov_trace_pc+0x3c/0x60 kernel/kcov.c:203 Code: 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 a4 15 00 00 85 c0 74 2b 8b 82 80 15 00 00 83 f8 02 75 20 <48> 8b 8a 88 15 00 00 8b 92 84 15 00 00 48 8b 01 48 83 c0 01 48 39 RSP: 0018:ffffc90003c9f588 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000006 RCX: 0000000000000000 RDX: ffff88807c8f5700 RSI: ffffffff83a3079a RDI: 0000000000000003 RBP: ffff88807ccf4d80 R08: 0000000000000000 R09: 0000000000000006 R10: ffffffff83a30787 R11: 0000000000000010 R12: 0000000000000010 R13: 000000000000014b R14: dffffc0000000000 R15: 0000000000000000 tomoyo_domain_quota_is_ok+0x31a/0x550 security/tomoyo/util.c:1092 tomoyo_supervisor+0x2f2/0xf00 security/tomoyo/common.c:2089 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline] tomoyo_path_permission security/tomoyo/file.c:587 [inline] tomoyo_path_permission+0x270/0x3a0 security/tomoyo/file.c:573 tomoyo_check_open_permission+0x33e/0x380 security/tomoyo/file.c:777 tomoyo_file_open security/tomoyo/tomoyo.c:311 [inline] tomoyo_file_open+0xa3/0xd0 security/tomoyo/tomoyo.c:306 security_file_open+0x45/0xb0 security/security.c:1635 do_dentry_open+0x353/0x1250 fs/open.c:809 do_open fs/namei.c:3426 [inline] path_openat+0x1cad/0x2750 fs/namei.c:3559 do_filp_open+0x1aa/0x400 fs/namei.c:3586 do_sys_openat2+0x16d/0x4d0 fs/open.c:1212 do_sys_open fs/open.c:1228 [inline] __do_compat_sys_open fs/open.c:1279 [inline] __se_compat_sys_open fs/open.c:1277 [inline] __ia32_compat_sys_open+0x119/0x1c0 fs/open.c:1277 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf6e68549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f44625fc EFLAGS: 00000296 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 0000000020000400 RCX: 000000000014103e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 00 65 48 add %ah,0x48(%rbp) 3: 8b 14 25 40 70 02 00 mov 0x27040,%edx a: a9 00 01 ff 00 test $0xff0100,%eax f: 74 0e je 0x1f 11: 85 c9 test %ecx,%ecx 13: 74 35 je 0x4a 15: 8b 82 a4 15 00 00 mov 0x15a4(%rdx),%eax 1b: 85 c0 test %eax,%eax 1d: 74 2b je 0x4a 1f: 8b 82 80 15 00 00 mov 0x1580(%rdx),%eax 25: 83 f8 02 cmp $0x2,%eax 28: 75 20 jne 0x4a * 2a: 48 8b 8a 88 15 00 00 mov 0x1588(%rdx),%rcx <-- trapping instruction 31: 8b 92 84 15 00 00 mov 0x1584(%rdx),%edx 37: 48 8b 01 mov (%rcx),%rax 3a: 48 83 c0 01 add $0x1,%rax 3e: 48 rex.W 3f: 39 .byte 0x39