============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- syz-executor.4/31712 is trying to acquire lock: 00000000fc71a269 (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 but task is already holding lock: 00000000fc71a269 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 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 5 locks held by syz-executor.4/31712: #0: 00000000c50698e7 (&mm->mmap_sem){++++}, at: __mm_populate+0x24e/0x350 mm/gup.c:1277 #1: 0000000018b4ca84 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] #1: 0000000018b4ca84 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: pte_alloc_one_map mm/memory.c:3479 [inline] #1: 0000000018b4ca84 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: alloc_set_pte+0xfbc/0x1a00 mm/memory.c:3608 #2: 00000000aad8a055 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #2: 00000000aad8a055 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115 #3: 00000000fc71a269 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 #4: 00000000dd6e0bd0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293 stack backtrace: CPU: 1 PID: 31712 Comm: syz-executor.4 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:1764 [inline] check_deadlock kernel/locking/lockdep.c:1808 [inline] validate_chain kernel/locking/lockdep.c:2404 [inline] __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152 uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479 tty_wakeup+0xd4/0x110 drivers/tty/tty_io.c:534 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1813 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1900 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1873 [inline] serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1916 serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu kernel/irq/handle.c:189 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:206 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_acquire+0x1ec/0x3c0 kernel/locking/lockdep.c:3911 Code: 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 b7 01 00 00 48 83 3d 09 2e a6 08 00 0f 84 2a 01 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b RSP: 0018:ffff8880a264f970 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd2 RAX: 1ffffffff13e3051 RBX: ffff888051730200 RCX: 0000000000006a30 RDX: dffffc0000000000 RSI: 00000000745c7177 RDI: 0000000000000286 RBP: ffff8880a203fee0 R08: ffffffff8cd4c6c0 R09: 0000000000000001 R10: ffff888051730ab0 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] pte_alloc_one_map mm/memory.c:3479 [inline] alloc_set_pte+0xfbc/0x1a00 mm/memory.c:3608 finish_fault+0x170/0x2c0 mm/memory.c:3673 do_read_fault mm/memory.c:3819 [inline] do_fault mm/memory.c:3944 [inline] handle_pte_fault mm/memory.c:4175 [inline] __handle_mm_fault+0x2768/0x41c0 mm/memory.c:4299 handle_mm_fault+0x436/0xb10 mm/memory.c:4336 faultin_page mm/gup.c:539 [inline] __get_user_pages+0x6f0/0x1710 mm/gup.c:745 populate_vma_page_range+0x200/0x290 mm/gup.c:1249 __mm_populate+0x1ea/0x350 mm/gup.c:1297 mm_populate include/linux/mm.h:2338 [inline] __do_sys_remap_file_pages mm/mmap.c:2907 [inline] __se_sys_remap_file_pages+0x7b9/0x7c0 mm/mmap.c:2817 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3079d5e409 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f30786d3168 EFLAGS: 00000246 ORIG_RAX: 00000000000000d8 RAX: ffffffffffffffda RBX: 00007f3079e70f80 RCX: 00007f3079d5e409 RDX: 0000000000000000 RSI: 0000000000200000 RDI: 00000000202ec000 RBP: 00007f3079db9367 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdd8810f2f R14: 00007f30786d3300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 08 00 or %al,(%rax) 2: 00 00 add %al,(%rax) 4: 00 00 add %al,(%rax) 6: 00 48 c1 add %cl,-0x3f(%rax) 9: e8 03 80 3c 10 callq 0x103c8011 e: 00 0f add %cl,(%rdi) 10: 85 b7 01 00 00 48 test %esi,0x48000001(%rdi) 16: 83 3d 09 2e a6 08 00 cmpl $0x0,0x8a62e09(%rip) # 0x8a62e26 1d: 0f 84 2a 01 00 00 je 0x14d 23: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 48 83 c4 18 add $0x18,%rsp 33: 5b pop %rbx 34: 5d pop %rbp 35: 41 5c pop %r12 37: 41 5d pop %r13 39: 41 5e pop %r14 3b: 41 5f pop %r15 3d: c3 retq 3e: 65 gs 3f: 8b .byte 0x8b