RDX: 000000000000ff2e RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007fffd237be40 R08: 0000000000000001 R09: 00007f310e230033
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
======================================================
WARNING: possible circular locking dependency detected
4.14.302-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor518/7969 is trying to acquire lock:
(console_owner){....}, at: [<ffffffff81440a47>] log_next kernel/printk/printk.c:495 [inline]
(console_owner){....}, at: [<ffffffff81440a47>] console_unlock+0x307/0xf20 kernel/printk/printk.c:2396
but task is already holding lock:
(&(&port->lock)->rlock){-.-.}, at: [<ffffffff835603ab>] tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:569
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&(&port->lock)->rlock){-.-.}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:160
tty_port_tty_get+0x1d/0x80 drivers/tty/tty_port.c:288
tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:46
serial8250_tx_chars+0x3fe/0xc70 drivers/tty/serial/8250/8250_port.c:1828
serial8250_handle_irq.part.0+0x2c7/0x390 drivers/tty/serial/8250/8250_port.c:1918
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1891 [inline]
serial8250_default_handle_irq+0x8a/0x1f0 drivers/tty/serial/8250/8250_port.c:1934
serial8250_interrupt+0xf3/0x210 drivers/tty/serial/8250/8250_core.c:129
__handle_irq_event_percpu+0xee/0x7f0 kernel/irq/handle.c:147
handle_irq_event_percpu kernel/irq/handle.c:187 [inline]
handle_irq_event+0xed/0x240 kernel/irq/handle.c:204
handle_edge_irq+0x224/0xc40 kernel/irq/chip.c:770
generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87
do_IRQ+0x93/0x1d0 arch/x86/kernel/irq.c:230
ret_from_intr+0x0/0x1e
arch_local_irq_restore arch/x86/include/asm/paravirt.h:779 [inline]
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irqrestore+0xa3/0xe0 kernel/locking/spinlock.c:192
spin_unlock_irqrestore include/linux/spinlock.h:372 [inline]
uart_write+0x2dd/0x560 drivers/tty/serial/serial_core.c:632
do_output_char+0x4f5/0x750 drivers/tty/n_tty.c:447
process_output drivers/tty/n_tty.c:514 [inline]
n_tty_write+0x3e3/0xda0 drivers/tty/n_tty.c:2345
do_tty_write drivers/tty/tty_io.c:959 [inline]
tty_write+0x410/0x740 drivers/tty/tty_io.c:1043
redirected_tty_write+0x9c/0xb0 drivers/tty/tty_io.c:1064
do_loop_readv_writev fs/read_write.c:698 [inline]
do_loop_readv_writev fs/read_write.c:682 [inline]
do_iter_write+0x3da/0x550 fs/read_write.c:956
vfs_writev+0x125/0x290 fs/read_write.c:999
do_writev+0xfc/0x2c0 fs/read_write.c:1034
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
-> #1 (&port_lock_key){-.-.}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:160
serial8250_console_write+0x8cb/0xb40 drivers/tty/serial/8250/8250_port.c:3281
call_console_drivers kernel/printk/printk.c:1727 [inline]
console_unlock+0x99d/0xf20 kernel/printk/printk.c:2409
vprintk_emit+0x224/0x620 kernel/printk/printk.c:1925
vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:409
printk+0x9e/0xbc kernel/printk/printk.c:1998
register_console+0x6f4/0xad0 kernel/printk/printk.c:2728
univ8250_console_init+0x2f/0x3a drivers/tty/serial/8250/8250_core.c:691
console_init+0x46/0x53 kernel/printk/printk.c:2809
start_kernel+0x521/0x763 init/main.c:638
secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240
-> #0 (console_owner){....}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
console_lock_spinning_enable kernel/printk/printk.c:1590 [inline]
console_unlock+0x36f/0xf20 kernel/printk/printk.c:2406
vprintk_emit+0x224/0x620 kernel/printk/printk.c:1925
vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:409
printk+0x9e/0xbc kernel/printk/printk.c:1998
fail_dump lib/fault-inject.c:44 [inline]
should_fail.cold+0xdf/0x149 lib/fault-inject.c:149
should_failslab+0xd6/0x130 mm/failslab.c:32
slab_pre_alloc_hook mm/slab.h:421 [inline]
slab_alloc mm/slab.c:3376 [inline]
__do_kmalloc mm/slab.c:3718 [inline]
__kmalloc+0x6d/0x400 mm/slab.c:3729
kmalloc include/linux/slab.h:493 [inline]
tty_buffer_alloc+0xc0/0x270 drivers/tty/tty_buffer.c:169
__tty_buffer_request_room+0x12c/0x290 drivers/tty/tty_buffer.c:268
tty_insert_flip_string_fixed_flag+0x8b/0x210 drivers/tty/tty_buffer.c:313
tty_insert_flip_string include/linux/tty_flip.h:36 [inline]
tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:570
pty_write+0xc3/0xf0 drivers/tty/pty.c:118
n_tty_write+0x85e/0xda0 drivers/tty/n_tty.c:2356
do_tty_write drivers/tty/tty_io.c:959 [inline]
tty_write+0x410/0x740 drivers/tty/tty_io.c:1043
__vfs_write+0xe4/0x630 fs/read_write.c:480
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
other info that might help us debug this:
Chain exists of:
console_owner --> &port_lock_key --> &(&port->lock)->rlock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&(&port->lock)->rlock);
lock(&port_lock_key);
lock(&(&port->lock)->rlock);
lock(console_owner);
*** DEADLOCK ***
6 locks held by syz-executor518/7969:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff8355c822>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
#1: (&tty->atomic_write_lock){+.+.}, at: [<ffffffff8354549d>] tty_write_lock drivers/tty/tty_io.c:885 [inline]
#1: (&tty->atomic_write_lock){+.+.}, at: [<ffffffff8354549d>] do_tty_write drivers/tty/tty_io.c:908 [inline]
#1: (&tty->atomic_write_lock){+.+.}, at: [<ffffffff8354549d>] tty_write+0x22d/0x740 drivers/tty/tty_io.c:1043
#2: (&tty->termios_rwsem){++++}, at: [<ffffffff835506da>] n_tty_write+0x18a/0xda0 drivers/tty/n_tty.c:2316
#3: (&ldata->output_lock){+.+.}, at: [<ffffffff83550d7b>] n_tty_write+0x82b/0xda0 drivers/tty/n_tty.c:2355
#4: (&(&port->lock)->rlock){-.-.}, at: [<ffffffff835603ab>] tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:569
#5: (console_lock){+.+.}, at: [<ffffffff814443a8>] vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:409
stack backtrace:
CPU: 1 PID: 7969 Comm: syz-executor518 Not tainted 4.14.302-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x281 lib/dump_stack.c:58
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1905 [inline]
check_prevs_add kernel/locking/lockdep.c:2022 [inline]
validate_chain kernel/locking/lockdep.c:2464 [inline]
__lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
console_lock_spinning_enable kernel/printk/printk.c:1590 [inline]
console_unlock+0x36f/0xf20 kernel/printk/printk.c:2406
vprintk_emit+0x224/0x620 kernel/printk/printk.c:1925
vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:409
printk+0x9e/0xbc kernel/printk/printk.c:1998
fail_dump lib/fault-inject.c:44 [inline]
should_fail.cold+0xdf/0x149 lib/fault-inject.c:149
should_failslab+0xd6/0x130 mm/failslab.c:32
slab_pre_alloc_hook mm/slab.h:421 [inline]
slab_alloc mm/slab.c:3376 [inline]
__do_kmalloc mm/slab.c:3718 [inline]
__kmalloc+0x6d/0x400 mm/slab.c:3729
kmalloc include/linux/slab.h:493 [inline]
tty_buffer_alloc+0xc0/0x270 drivers/tty/tty_buffer.c:169
__tty_buffer_request_room+0x12c/0x290 drivers/tty/tty_buffer.c:268
tty_insert_flip_string_fixed_flag+0x8b/0x210 drivers/tty/tty_buffer.c:313
tty_insert_flip_string include/linux/tty_flip.h:36 [inline]
tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:570
pty_write+0xc3/0xf0 drivers/tty/pty.c:118
n_tty_write+0x85e/0xda0 drivers/tty/n_tty.c:2356
do_tty_write drivers/tty/tty_io.c:959 [inline]
tty_write+0x410/0x740 drivers/tty/tty_io.c:1043
__vfs_write+0xe4/0x630 fs/read_write.c:480
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f310e26f679
RSP: 002b:00007fffd237be38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f310e26f679
RDX: 000000000000ff2e RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007fffd237be40 R08: 0000000000000001 R09: 00007f310e230033
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000