======================================================
WARNING: possible circular locking dependency detected
5.15.182-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.316/5670 is trying to acquire lock:
ffff8880276ac5a8 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0x5c/0x1050 kernel/sched/core.c:4030
but task is already holding lock:
ffff88801fad0dd8 (&port->delta_msr_wait){-...}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline]
ffff88801fad0dd8 (&port->delta_msr_wait){-...}-{2:2}, at: __wake_up+0xed/0x180 kernel/sched/wait.c:157
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&port->delta_msr_wait){-...}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
__wake_up_common_lock kernel/sched/wait.c:137 [inline]
__wake_up+0xed/0x180 kernel/sched/wait.c:157
serial8250_modem_status+0x1f1/0x270 drivers/tty/serial/8250/8250_port.c:1859
serial8250_handle_irq+0x438/0x610 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:233 [inline]
__common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
uart_update_mctrl drivers/tty/serial/serial_core.c:157 [inline]
uart_tiocmset+0x22e/0x2c0 drivers/tty/serial/serial_core.c:1094
tty_tiocmset drivers/tty/tty_io.c:2592 [inline]
tty_ioctl+0x9c8/0xc20 drivers/tty/tty_io.c:2785
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #3 (&port_lock_key){-...}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
serial8250_console_write+0x170/0xf80 drivers/tty/serial/8250/8250_port.c:3363
call_console_drivers kernel/printk/printk.c:-1 [inline]
console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
register_console+0x682/0x960 kernel/printk/printk.c:3107
univ8250_console_init+0x41/0x50 drivers/tty/serial/8250/8250_core.c:690
console_init+0x177/0x5d0 kernel/printk/printk.c:3207
start_kernel+0x2f9/0x530 init/main.c:1076
secondary_startup_64_no_verify+0xb1/0xbb
-> #2 (console_owner){-...}-{0:0}:
console_lock_spinning_enable+0x51/0x60 kernel/printk/printk.c:1805
console_unlock+0x9f8/0x1200 kernel/printk/printk.c:2741
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
fail_dump lib/fault-inject.c:45 [inline]
should_fail+0x36d/0x4c0 lib/fault-inject.c:146
strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:295
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:194 [inline]
____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:300 [inline]
bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:296
0xffffffffa00185c9
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:621 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x26e/0x320 kernel/trace/bpf_trace.c:1916
trace_sched_switch include/trace/events/sched.h:220 [inline]
__schedule+0x1d8b/0x43b0 kernel/sched/core.c:6373
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
____sys_sendmsg+0x3ae/0x8c0 net/socket.c:2421
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg+0x190/0x250 net/socket.c:2526
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #1 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
rq_lock kernel/sched/sched.h:1621 [inline]
task_fork_fair+0x5c/0x350 kernel/sched/fair.c:11499
sched_cgroup_fork+0x2c6/0x320 kernel/sched/core.c:4466
copy_process+0x22bd/0x3e60 kernel/fork.c:2319
kernel_clone+0x219/0x930 kernel/fork.c:2603
kernel_thread+0xc8/0x120 kernel/fork.c:2655
rest_init+0x21/0x330 init/main.c:706
start_kernel+0x486/0x530 init/main.c:1140
secondary_startup_64_no_verify+0xb1/0xbb
-> #0 (&p->pi_lock){-.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
try_to_wake_up+0x5c/0x1050 kernel/sched/core.c:4030
__wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:108
__wake_up_common_lock kernel/sched/wait.c:138 [inline]
__wake_up+0x108/0x180 kernel/sched/wait.c:157
serial8250_modem_status+0x1f1/0x270 drivers/tty/serial/8250/8250_port.c:1859
serial8250_handle_irq+0x438/0x610 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:233 [inline]
__common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
uart_update_mctrl drivers/tty/serial/serial_core.c:157 [inline]
uart_tiocmset+0x22e/0x2c0 drivers/tty/serial/serial_core.c:1094
tty_tiocmset drivers/tty/tty_io.c:2592 [inline]
tty_ioctl+0x9c8/0xc20 drivers/tty/tty_io.c:2785
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
other info that might help us debug this:
Chain exists of:
&p->pi_lock --> &port_lock_key --> &port->delta_msr_wait
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port->delta_msr_wait);
lock(&port_lock_key);
lock(&port->delta_msr_wait);
lock(&p->pi_lock);
*** DEADLOCK ***
4 locks held by syz.4.316/5670:
#0: ffff88801fad0e90 (&port->mutex){+.+.}-{3:3}, at: uart_tiocmset+0x54/0x2c0 drivers/tty/serial/serial_core.c:1088
#1: ffff88807530a9b0 (&i->lock){-...}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#1: ffff88807530a9b0 (&i->lock){-...}-{2:2}, at: serial8250_interrupt+0x3e/0x1c0 drivers/tty/serial/8250/8250_core.c:117
#2: ffffffff963c8420 (&port_lock_key){-...}-{2:2}, at: serial8250_handle_irq+0x6c/0x610 drivers/tty/serial/8250/8250_port.c:1895
#3: ffff88801fad0dd8 (&port->delta_msr_wait){-...}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline]
#3: ffff88801fad0dd8 (&port->delta_msr_wait){-...}-{2:2}, at: __wake_up+0xed/0x180 kernel/sched/wait.c:157
stack backtrace:
CPU: 0 PID: 5670 Comm: syz.4.316 Not tainted 5.15.182-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
try_to_wake_up+0x5c/0x1050 kernel/sched/core.c:4030
__wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:108
__wake_up_common_lock kernel/sched/wait.c:138 [inline]
__wake_up+0x108/0x180 kernel/sched/wait.c:157
serial8250_modem_status+0x1f1/0x270 drivers/tty/serial/8250/8250_port.c:1859
serial8250_handle_irq+0x438/0x610 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:233 [inline]
__common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 ee 4f d3 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> c6 cf a6 f7 65 8b 05 67 e3 57 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90002edfdc0 EFLAGS: 00000206
RAX: 16f889dc85884e00 RBX: 0000000000000a06 RCX: 16f889dc85884e00
RDX: dffffc0000000000 RSI: ffffffff8a0b0fc0 RDI: 0000000000000001
RBP: ffffc90002edfe50 R08: dffffc0000000000 R09: fffffbfff1ff3423
R10: fffffbfff1ff3423 R11: 1ffffffff1ff3422 R12: dffffc0000000000
R13: ffffffff963c8558 R14: ffffffff963c8408 R15: 1ffff920005dbfb8
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
uart_update_mctrl drivers/tty/serial/serial_core.c:157 [inline]
uart_tiocmset+0x22e/0x2c0 drivers/tty/serial/serial_core.c:1094
tty_tiocmset drivers/tty/tty_io.c:2592 [inline]
tty_ioctl+0x9c8/0xc20 drivers/tty/tty_io.c:2785
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4cc891e969
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4cc6765038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4cc8b46080 RCX: 00007f4cc891e969
RDX: 0000200000000140 RSI: 0000000000005418 RDI: 000000000000000b
RBP: 00007f4cc89a0ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f4cc8b46080 R15: 00007ffe98dbfa88
</TASK>
vkms_vblank_simulate: vblank timer overrun
----------------
Code disassembly (best guess):
0: 74 05 je 0x7
2: e8 ee 4f d3 f7 call 0xf7d34ff5
7: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp)
e: 00 00
10: 9c pushf
11: 8f 44 24 20 pop 0x20(%rsp)
15: f6 44 24 21 02 testb $0x2,0x21(%rsp)
1a: 75 4b jne 0x67
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 c6 cf a6 f7 call 0xf7a6cff5 <-- trapping instruction
2f: 65 8b 05 67 e3 57 76 mov %gs:0x7657e367(%rip),%eax # 0x7657e39d
36: 85 c0 test %eax,%eax
38: 74 3c je 0x76
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss