syzbot


possible deadlock in tty_port_default_wakeup

Status: upstream: reported on 2022/11/26 17:05
Reported-by: syzbot+2bd4a8abdc688d6abb1d@syzkaller.appspotmail.com
First crash: 74d, last: 5d00h

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc6-syzkaller-00003-g22b8077d0fce #0 Not tainted
------------------------------------------------------
syz-executor.1/27085 is trying to acquire lock:
ffffffff8d5fc528 (zonelist_update_seq.seqcount){...-}-{0:0}, at: read_seqbegin include/linux/seqlock.h:836 [inline]
ffffffff8d5fc528 (zonelist_update_seq.seqcount){...-}-{0:0}, at: zonelist_iter_begin mm/page_alloc.c:4722 [inline]
ffffffff8d5fc528 (zonelist_update_seq.seqcount){...-}-{0:0}, at: __alloc_pages_slowpath+0x297/0x2120 mm/page_alloc.c:5044

but task is already holding lock:
ffff88802d920958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x39/0x3b0 drivers/tty/tty_buffer.c:628

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&port->lock){-.-.}-{2:2}:
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5668
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       tty_port_tty_get drivers/tty/tty_port.c:327 [inline]
       tty_port_default_wakeup+0x1f/0xf0 drivers/tty/tty_port.c:68
       serial8250_tx_chars+0x6be/0x8c0 drivers/tty/serial/8250/8250_port.c:1858
       serial8250_handle_irq+0x3e3/0x560 drivers/tty/serial/8250/8250_port.c:1948
       serial8250_default_handle_irq+0xaf/0x190 drivers/tty/serial/8250/8250_port.c:1968
       serial8250_interrupt+0xa3/0x1e0 drivers/tty/serial/8250/8250_core.c:127
       __handle_irq_event_percpu+0x200/0x620 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x83/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x245/0xbe0 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:231 [inline]
       __common_interrupt+0xce/0x1e0 arch/x86/kernel/irq.c:250
       common_interrupt+0x9f/0xc0 arch/x86/kernel/irq.c:240
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:640
       native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
       acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
       acpi_idle_do_entry drivers/acpi/processor_idle.c:570 [inline]
       acpi_idle_enter+0x43d/0x800 drivers/acpi/processor_idle.c:707
       cpuidle_enter_state+0x50b/0xf50 drivers/cpuidle/cpuidle.c:239
       cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:356
       call_cpuidle kernel/sched/idle.c:155 [inline]
       cpuidle_idle_call kernel/sched/idle.c:236 [inline]
       do_idle+0x3da/0x680 kernel/sched/idle.c:303
       cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
       rest_init+0x24f/0x270 init/main.c:732
       arch_call_rest_init+0xa/0x10 init/main.c:894
       start_kernel+0x48e/0x540 init/main.c:1148
       secondary_startup_64_no_verify+0xcf/0xdb

-> #2 (&port_lock_key){-.-.}-{2:2}:
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5668
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       serial8250_console_write+0x1a9/0x1ac0 drivers/tty/serial/8250/8250_port.c:3394
       call_console_driver kernel/printk/printk.c:2033 [inline]
       console_emit_next_record+0x7aa/0xa70 kernel/printk/printk.c:2825
       console_flush_all+0x2d4/0x6f0
       console_unlock+0xfa/0x270 kernel/printk/printk.c:2966
       vprintk_emit+0xd1/0x1e0 kernel/printk/printk.c:2359
       _printk+0xcf/0x110 kernel/printk/printk.c:2380
       register_console+0xb38/0x1110 kernel/printk/printk.c:3417
       univ8250_console_init+0x41/0x50 drivers/tty/serial/8250/8250_core.c:688
       console_init+0x5d/0xb0 kernel/printk/printk.c:3560
       start_kernel+0x2fc/0x540 init/main.c:1077
       secondary_startup_64_no_verify+0xcf/0xdb

-> #1 (console_owner){-.-.}-{0:0}:
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5668
       console_lock_spinning_enable+0x52/0x60 kernel/printk/printk.c:1889
       console_emit_next_record+0x6c9/0xa70 kernel/printk/printk.c:2822
       console_flush_all+0x2d4/0x6f0
       console_unlock+0xfa/0x270 kernel/printk/printk.c:2966
       vprintk_emit+0xd1/0x1e0 kernel/printk/printk.c:2359
       _printk+0xcf/0x110 kernel/printk/printk.c:2380
       build_zonelists+0x3b0/0x450 mm/page_alloc.c:6497
       __build_all_zonelists+0x108/0x180 mm/page_alloc.c:6610
       build_all_zonelists_init+0x1f/0x180 mm/page_alloc.c:6635
       build_all_zonelists+0x3d/0x2f0 mm/page_alloc.c:6668
       start_kernel+0xd6/0x540 init/main.c:971
       secondary_startup_64_no_verify+0xcf/0xdb

-> #0 (zonelist_update_seq.seqcount){...-}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x184a/0x6470 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5668
       seqcount_lockdep_reader_access+0xe9/0x1e0 include/linux/seqlock.h:102
       read_seqbegin include/linux/seqlock.h:836 [inline]
       zonelist_iter_begin mm/page_alloc.c:4722 [inline]
       __alloc_pages_slowpath+0x297/0x2120 mm/page_alloc.c:5044
       __alloc_pages+0x3d4/0x560 mm/page_alloc.c:5562
       alloc_slab_page+0xbd/0x190 mm/slub.c:1851
       allocate_slab+0x5e/0x3c0 mm/slub.c:1998
       new_slab mm/slub.c:2051 [inline]
       ___slab_alloc+0x7f4/0xeb0 mm/slub.c:3193
       __slab_alloc mm/slub.c:3292 [inline]
       __slab_alloc_node mm/slub.c:3345 [inline]
       slab_alloc_node mm/slub.c:3442 [inline]
       __kmem_cache_alloc_node+0x25b/0x340 mm/slub.c:3491
       __do_kmalloc_node mm/slab_common.c:967 [inline]
       __kmalloc+0x9e/0x190 mm/slab_common.c:981
       kmalloc include/linux/slab.h:584 [inline]
       tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline]
       __tty_buffer_request_room+0x1e3/0x550 drivers/tty/tty_buffer.c:278
       tty_insert_flip_string_fixed_flag drivers/tty/tty_buffer.c:327 [inline]
       tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
       tty_insert_flip_string_and_push_buffer+0x91/0x3b0 drivers/tty/tty_buffer.c:629
       n_tty_write+0x62c/0x12e0 drivers/tty/n_tty.c:2373
       do_tty_write drivers/tty/tty_io.c:1018 [inline]
       file_tty_write+0x542/0x8d0 drivers/tty/tty_io.c:1089
       call_write_iter include/linux/fs.h:2189 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x7b5/0xbb0 fs/read_write.c:584
       ksys_write+0x19b/0x2c0 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  zonelist_update_seq.seqcount --> &port_lock_key --> &port->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&port->lock);
                               lock(&port_lock_key);
                               lock(&port->lock);
  lock(zonelist_update_seq.seqcount);

 *** DEADLOCK ***

5 locks held by syz-executor.1/27085:
 #0: ffff88808b7c1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffff88808b7c1130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:944 [inline]
 #1: ffff88808b7c1130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:967 [inline]
 #1: ffff88808b7c1130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write+0x226/0x8d0 drivers/tty/tty_io.c:1089
 #2: ffff88808b7c12e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x248/0x12e0 drivers/tty/n_tty.c:2333
 #3: ffffc900047ed380 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x5ea/0x12e0 drivers/tty/n_tty.c:2372
 #4: ffff88802d920958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x39/0x3b0 drivers/tty/tty_buffer.c:628

stack backtrace:
CPU: 0 PID: 27085 Comm: syz-executor.1 Not tainted 6.2.0-rc6-syzkaller-00003-g22b8077d0fce #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f9/0x3b0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x184a/0x6470 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5668
 seqcount_lockdep_reader_access+0xe9/0x1e0 include/linux/seqlock.h:102
 read_seqbegin include/linux/seqlock.h:836 [inline]
 zonelist_iter_begin mm/page_alloc.c:4722 [inline]
 __alloc_pages_slowpath+0x297/0x2120 mm/page_alloc.c:5044
 __alloc_pages+0x3d4/0x560 mm/page_alloc.c:5562
 alloc_slab_page+0xbd/0x190 mm/slub.c:1851
 allocate_slab+0x5e/0x3c0 mm/slub.c:1998
 new_slab mm/slub.c:2051 [inline]
 ___slab_alloc+0x7f4/0xeb0 mm/slub.c:3193
 __slab_alloc mm/slub.c:3292 [inline]
 __slab_alloc_node mm/slub.c:3345 [inline]
 slab_alloc_node mm/slub.c:3442 [inline]
 __kmem_cache_alloc_node+0x25b/0x340 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:967 [inline]
 __kmalloc+0x9e/0x190 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline]
 __tty_buffer_request_room+0x1e3/0x550 drivers/tty/tty_buffer.c:278
 tty_insert_flip_string_fixed_flag drivers/tty/tty_buffer.c:327 [inline]
 tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
 tty_insert_flip_string_and_push_buffer+0x91/0x3b0 drivers/tty/tty_buffer.c:629
 n_tty_write+0x62c/0x12e0 drivers/tty/n_tty.c:2373
 do_tty_write drivers/tty/tty_io.c:1018 [inline]
 file_tty_write+0x542/0x8d0 drivers/tty/tty_io.c:1089
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7b5/0xbb0 fs/read_write.c:584
 ksys_write+0x19b/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc4f968c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007fc4fa331168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc4f97abf80 RCX: 00007fc4f968c0c9
RDX: 000000000000ff2e RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007fc4f96e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffcf4eae8f R14: 00007fc4fa331300 R15: 0000000000022000
 </TASK>

Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce-smack-root 2023/01/31 09:51 upstream 22b8077d0fce 9dfcf09c .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in tty_port_default_wakeup
ci-qemu-upstream 2022/12/23 16:44 upstream 8395ae05cb5a 9da18ae8 .config console log report info possible deadlock in tty_port_default_wakeup
ci-qemu-upstream 2022/12/08 10:47 upstream 479174d402bc 1034e5fa .config console log report info possible deadlock in tty_port_default_wakeup
ci-qemu-upstream 2022/12/01 01:18 upstream 04aa64375f48 4c2a66e8 .config console log report info possible deadlock in tty_port_default_wakeup
ci-qemu-upstream 2022/11/28 15:16 upstream b7b275e60bcd 950c3e02 .config console log report info possible deadlock in tty_port_default_wakeup
ci-qemu-upstream 2022/11/22 17:00 upstream eb7081409f94 1c8e10bc .config console log report info possible deadlock in tty_port_default_wakeup
* Struck through repros no longer work on HEAD.