======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc5-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/31478 is trying to acquire lock:
ffffffff8c70c660 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable+0x2d/0x60 kernel/printk/printk.c:1787
but task is already holding lock:
ffff88802f6ae958 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc5/0x170 drivers/tty/pty.c:120
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&port->lock){-.-.}-{2:2}:
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb3/0x100 kernel/locking/spinlock.c:159
tty_port_tty_get+0x21/0xe0 drivers/tty/tty_port.c:289
tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:48
serial8250_tx_chars+0x68e/0x8a0 drivers/tty/serial/8250/8250_port.c:1844
serial8250_handle_irq+0x2fd/0x3e0 drivers/tty/serial/8250/8250_port.c:1931
serial8250_default_handle_irq+0xaf/0x190 drivers/tty/serial/8250/8250_port.c:1948
serial8250_interrupt+0xa3/0x1e0 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x20a/0x6d0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0x10a/0x300 kernel/irq/handle.c:213
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+0x9c/0xc0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:191
spin_unlock_irqrestore include/linux/spinlock.h:409 [inline]
uart_write+0x69d/0x910 drivers/tty/serial/serial_core.c:591
do_output_char+0x638/0x940 drivers/tty/n_tty.c:444
process_output drivers/tty/n_tty.c:511 [inline]
n_tty_write+0xe33/0x1310 drivers/tty/n_tty.c:2300
do_tty_write drivers/tty/tty_io.c:1038 [inline]
file_tty_write+0x5c5/0x9a0 drivers/tty/tty_io.c:1110
do_iter_readv_writev+0x566/0x770 include/linux/fs.h:2108
do_iter_write+0x16c/0x5f0 fs/read_write.c:866
vfs_writev fs/read_write.c:939 [inline]
do_writev+0x240/0x440 fs/read_write.c:982
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #1 (&port_lock_key){-.-.}-{2:2}:
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb3/0x100 kernel/locking/spinlock.c:159
serial8250_console_write+0x17a/0xee0 drivers/tty/serial/8250/8250_port.c:3344
call_console_drivers kernel/printk/printk.c:1938 [inline]
console_unlock+0x9aa/0xec0 kernel/printk/printk.c:2643
vprintk_emit+0x21a/0x2f0 kernel/printk/printk.c:2174
vprintk+0x30d/0x370 kernel/printk/printk_safe.c:392
printk+0xc0/0x108 kernel/printk/printk.c:2216
register_console+0x6c0/0x9a0 kernel/printk/printk.c:2991
univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:680
console_init+0x52/0x97 kernel/printk/printk.c:3091
start_kernel+0x311/0x549 init/main.c:1049
secondary_startup_64_no_verify+0xb0/0xbb
-> #0 (console_owner){-...}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3051 [inline]
check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
validate_chain kernel/locking/lockdep.c:3789 [inline]
__lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
console_lock_spinning_enable+0x52/0x60 kernel/printk/printk.c:1790
console_unlock+0x6f5/0xec0 kernel/printk/printk.c:2640
vprintk_emit+0x21a/0x2f0 kernel/printk/printk.c:2174
vprintk+0x30d/0x370 kernel/printk/printk_safe.c:392
printk+0xc0/0x108 kernel/printk/printk.c:2216
fail_dump lib/fault-inject.c:45 [inline]
should_fail+0x366/0x4b0 lib/fault-inject.c:146
should_failslab+0x5/0x20 mm/slab_common.c:1326
slab_pre_alloc_hook mm/slab.h:494 [inline]
slab_alloc_node mm/slub.c:2877 [inline]
slab_alloc mm/slub.c:2964 [inline]
__kmalloc+0x89/0x390 mm/slub.c:4108
kmalloc include/linux/slab.h:596 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x1f0/0x540 drivers/tty/tty_buffer.c:275
tty_insert_flip_string_fixed_flag+0x92/0x2c0 drivers/tty/tty_buffer.c:321
tty_insert_flip_string include/linux/tty_flip.h:39 [inline]
pty_write+0xe9/0x170 drivers/tty/pty.c:122
gsmld_write+0xae/0xc0 drivers/tty/n_gsm.c:2597
do_tty_write drivers/tty/tty_io.c:1038 [inline]
file_tty_write+0x5c5/0x9a0 drivers/tty/tty_io.c:1110
call_write_iter include/linux/fs.h:2114 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0xa39/0xc90 fs/read_write.c:605
ksys_write+0x171/0x2a0 fs/read_write.c:658
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of:
console_owner --> &port_lock_key --> &port->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port->lock);
lock(&port_lock_key);
lock(&port->lock);
lock(console_owner);
*** DEADLOCK ***
4 locks held by syz-executor.4/31478:
#0: ffff88807e563098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffff88807e563130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:961 [inline]
#1: ffff88807e563130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:984 [inline]
#1: ffff88807e563130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write+0x271/0x9a0 drivers/tty/tty_io.c:1110
#2: ffff88802f6ae958 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc5/0x170 drivers/tty/pty.c:120
#3: ffffffff8c5f4340 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0x201/0x2f0 kernel/printk/printk.c:2173
stack backtrace:
CPU: 1 PID: 31478 Comm: syz-executor.4 Not tainted 5.14.0-rc5-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+0x1ae/0x29f lib/dump_stack.c:105
print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131
check_prev_add kernel/locking/lockdep.c:3051 [inline]
check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
validate_chain kernel/locking/lockdep.c:3789 [inline]
__lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
console_lock_spinning_enable+0x52/0x60 kernel/printk/printk.c:1790
console_unlock+0x6f5/0xec0 kernel/printk/printk.c:2640
vprintk_emit+0x21a/0x2f0 kernel/printk/printk.c:2174
vprintk+0x30d/0x370 kernel/printk/printk_safe.c:392
printk+0xc0/0x108 kernel/printk/printk.c:2216
fail_dump lib/fault-inject.c:45 [inline]
should_fail+0x366/0x4b0 lib/fault-inject.c:146
should_failslab+0x5/0x20 mm/slab_common.c:1326
slab_pre_alloc_hook mm/slab.h:494 [inline]
slab_alloc_node mm/slub.c:2877 [inline]
slab_alloc mm/slub.c:2964 [inline]
__kmalloc+0x89/0x390 mm/slub.c:4108
kmalloc include/linux/slab.h:596 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x1f0/0x540 drivers/tty/tty_buffer.c:275
tty_insert_flip_string_fixed_flag+0x92/0x2c0 drivers/tty/tty_buffer.c:321
tty_insert_flip_string include/linux/tty_flip.h:39 [inline]
pty_write+0xe9/0x170 drivers/tty/pty.c:122
gsmld_write+0xae/0xc0 drivers/tty/n_gsm.c:2597
do_tty_write drivers/tty/tty_io.c:1038 [inline]
file_tty_write+0x5c5/0x9a0 drivers/tty/tty_io.c:1110
call_write_iter include/linux/fs.h:2114 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0xa39/0xc90 fs/read_write.c:605
ksys_write+0x171/0x2a0 fs/read_write.c:658
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0b312d9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 000000000000fe8d RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00007f0b312d91d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffcc2862c2f R14: 00007f0b312d9300 R15: 0000000000022000