============================================ WARNING: possible recursive locking detected 5.16.0-rc3-syzkaller #0 Not tainted -------------------------------------------- syz-executor.3/15198 is trying to acquire lock: ffffffff9078c3f0 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577 but task is already holding lock: ffffffff9078c3f0 (&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.3/15198: #0: ffffffff8c359898 (tomoyo_ss){....}-{0:0}, at: tomoyo_path_perm+0x1c1/0x400 security/tomoyo/file.c:847 #1: ffff888019aa59b0 (&i->lock){-.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #1: ffff888019aa59b0 (&i->lock){-.-.}-{2:2}, at: serial8250_interrupt+0x3a/0x200 drivers/tty/serial/8250/8250_core.c:116 #2: ffffffff9078c3f0 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908 #3: ffff88807b9ad098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273 stack backtrace: CPU: 0 PID: 15198 Comm: syz-executor.3 Not tainted 5.16.0-rc3-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:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:200 Code: 00 00 e9 36 1c 63 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 39 c5 8a 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc90002bdf900 EFLAGS: 00000202 RAX: 0000000080000000 RBX: 0000000000000008 RCX: 0000000080000000 RDX: ffff888040a40000 RSI: ffffffff83a3233a RDI: 0000000000000003 RBP: ffff888078399880 R08: 0000000000000000 R09: 0000000000000008 R10: ffffffff83a32327 R11: 0000000000000010 R12: 0000000000000100 R13: 000000000000027a R14: dffffc0000000000 R15: 0000000000000001 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_path_perm+0x2f0/0x400 security/tomoyo/file.c:838 security_inode_getattr+0xcf/0x140 security/security.c:1334 vfs_getattr fs/stat.c:157 [inline] vfs_fstat+0x43/0xb0 fs/stat.c:182 __do_sys_newfstat+0x81/0x100 fs/stat.c:422 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7faa59705b35 Code: bc ff ff ff 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 41 89 f8 89 f7 48 89 d6 41 83 f8 01 77 2a b8 05 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 c3 66 90 48 c7 c2 bc ff ff ff f7 d8 64 89 RSP: 002b:00007ffd8b11b9c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 0000000000001794 RCX: 00007faa59705b35 RDX: 00007ffd8b11b9d0 RSI: 00007ffd8b11b9d0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000001 R09: 00007ffd8b11cc10 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd8b11b9d0 R13: 00007ffd8b11cc10 R14: 0000000000000011 R15: 00007ffd8b11cc50 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: e9 36 1c 63 02 jmpq 0x2631c3d 7: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) d: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 14: e8 b4 ff ff ff callq 0xffffffcd 19: 31 c0 xor %eax,%eax 1b: c3 retq 1c: 90 nop 1d: 65 8b 05 39 c5 8a 7e mov %gs:0x7e8ac539(%rip),%eax # 0x7e8ac55d 24: 89 c1 mov %eax,%ecx 26: 48 8b 34 24 mov (%rsp),%rsi * 2a: 81 e1 00 01 00 00 and $0x100,%ecx <-- trapping instruction 30: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx 37: 02 00 39: a9 00 01 ff 00 test $0xff0100,%eax 3e: 74 0e je 0x4e