FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.6987/29742 is trying to acquire lock:
ffffffff8c91f2e0 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8c91f2e0 (console_owner){-...}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774
but task is already holding lock:
ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
raw_spin_rq_lock kernel/sched/sched.h:1355 [inline]
rq_lock kernel/sched/sched.h:1645 [inline]
task_fork_fair+0x5c/0x350 kernel/sched/fair.c:11901
sched_cgroup_fork+0x32c/0x3c0 kernel/sched/core.c:4685
copy_process+0x24b8/0x4020 kernel/fork.c:2459
kernel_clone+0x225/0x8b0 kernel/fork.c:2757
user_mode_thread+0xda/0x130 kernel/fork.c:2833
rest_init+0x23/0x300 init/main.c:710
start_kernel+0x0/0x539 init/main.c:905
start_kernel+0x490/0x539 init/main.c:1152
secondary_startup_64_no_verify+0xcf/0xdb
-> #3 (&p->pi_lock){-.-.}-{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
try_to_wake_up+0x5c/0x1080 kernel/sched/core.c:4111
__wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:107
__wake_up_common_lock kernel/sched/wait.c:138 [inline]
__wake_up+0x10e/0x190 kernel/sched/wait.c:160
tty_port_default_wakeup+0x9e/0xf0 drivers/tty/tty_port.c:71
serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1854
serial8250_handle_irq+0x516/0x6d0 drivers/tty/serial/8250/8250_port.c:1961
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1981
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x298/0xa30 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0x87/0x1e0 kernel/irq/handle.c:210
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:682
native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
default_idle+0xb/0x10 arch/x86/kernel/process.c:741
default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1fc/0x570 kernel/sched/idle.c:303
cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xcf/0xdb
-> #2 (&tty->write_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+0xf4/0x190 kernel/sched/wait.c:160
tty_port_default_wakeup+0x9e/0xf0 drivers/tty/tty_port.c:71
serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1854
serial8250_handle_irq+0x516/0x6d0 drivers/tty/serial/8250/8250_port.c:1961
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1981
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x298/0xa30 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0x87/0x1e0 kernel/irq/handle.c:210
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:682
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_write+0x68a/0x910 drivers/tty/serial/serial_core.c:602
process_output_block drivers/tty/n_tty.c:586 [inline]
n_tty_write+0xd1a/0x11c0 drivers/tty/n_tty.c:2377
do_tty_write drivers/tty/tty_io.c:1018 [inline]
file_tty_write+0x4dd/0x860 drivers/tty/tty_io.c:1089
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #1 (&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+0x169/0x17a0 drivers/tty/serial/8250/8250_port.c:3432
call_console_driver kernel/printk/printk.c:1977 [inline]
console_emit_next_record+0x947/0xc90 kernel/printk/printk.c:2777
console_flush_all kernel/printk/printk.c:-1 [inline]
console_unlock+0x223/0x630 kernel/printk/printk.c:2906
vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
_printk+0xcc/0x110 kernel/printk/printk.c:2328
register_console+0x6c6/0x9c0 kernel/printk/printk.c:3269
univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:687
console_init+0x1bc/0x78e kernel/printk/printk.c:3359
start_kernel+0x303/0x539 init/main.c:1088
secondary_startup_64_no_verify+0xcf/0xdb
-> #0 (console_owner){-...}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
console_emit_next_record+0x84c/0xc90 kernel/printk/printk.c:2774
console_flush_all kernel/printk/printk.c:-1 [inline]
console_unlock+0x223/0x630 kernel/printk/printk.c:2906
vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
_printk+0xcc/0x110 kernel/printk/printk.c:2328
fail_dump lib/fault-inject.c:45 [inline]
should_fail_ex+0x37a/0x4d0 lib/fault-inject.c:147
strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
bpf_prog_02a70dbeb5f742df+0x3a/0x3c
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5229 [inline]
__schedule+0xe99/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
__syscall_enter_from_user_work kernel/entry/common.c:97 [inline]
syscall_enter_from_user_mode+0x2e/0x80 kernel/entry/common.c:118
do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77
entry_SYSCALL_64_after_hwframe+0x68/0xd2
other info that might help us debug this:
Chain exists of:
console_owner --> &p->pi_lock --> &rq->__lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&rq->__lock);
lock(&p->pi_lock);
lock(&rq->__lock);
lock(console_owner);
*** DEADLOCK ***
3 locks held by syz.4.6987/29742:
#0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
#1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
#1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324
#2: ffffffff8c91f3c0 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328
stack backtrace:
CPU: 1 PID: 29742 Comm: syz.4.6987 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
console_emit_next_record+0x84c/0xc90 kernel/printk/printk.c:2774
console_flush_all kernel/printk/printk.c:-1 [inline]
console_unlock+0x223/0x630 kernel/printk/printk.c:2906
vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
_printk+0xcc/0x110 kernel/printk/printk.c:2328
fail_dump lib/fault-inject.c:45 [inline]
should_fail_ex+0x37a/0x4d0 lib/fault-inject.c:147
strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
bpf_prog_02a70dbeb5f742df+0x3a/0x3c
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5229 [inline]
__schedule+0xe99/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:99 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2e/0x80 kernel/entry/common.c:118
Code: 89 f3 49 89 fe 48 8b 7c 24 10 e8 ed fa ff ff 66 90 66 90 e8 54 ca 76 f7 e8 cf c8 76 f7 fb 65 48 8b 05 26 fc f1 75 48 8b 70 08 <40> f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 81 72 5d f7 48 89 d8 5b 41
RSP: 0018:ffffc90010717f08 EFLAGS: 00000286
RAX: ffff888033d89dc0 RBX: 000000000000002e RCX: 27fdcc09e40b7300
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8abef920
RBP: ffffc90010717f48 R08: dffffc0000000000 R09: fffffbfff1bfe1c6
R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90010717f58 R15: 0000000000000000
do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff214d8f749
Code: Unable to access opcode bytes at 0x7ff214d8f71f.
RSP: 002b:00007ff215b51038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff214fe5fa0 RCX: 00007ff214d8f749
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007ff215b51090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ff214fe6038 R14: 00007ff214fe5fa0 R15: 00007ffc1ca456d8
CPU: 1 PID: 29742 Comm: syz.4.6987 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
fail_dump lib/fault-inject.c:52 [inline]
should_fail_ex+0x399/0x4d0 lib/fault-inject.c:147
strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline]
bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
bpf_prog_02a70dbeb5f742df+0x3a/0x3c
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5229 [inline]
__schedule+0xe99/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:99 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2e/0x80 kernel/entry/common.c:118
Code: 89 f3 49 89 fe 48 8b 7c 24 10 e8 ed fa ff ff 66 90 66 90 e8 54 ca 76 f7 e8 cf c8 76 f7 fb 65 48 8b 05 26 fc f1 75 48 8b 70 08 <40> f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 81 72 5d f7 48 89 d8 5b 41
RSP: 0018:ffffc90010717f08 EFLAGS: 00000286
RAX: ffff888033d89dc0 RBX: 000000000000002e RCX: 27fdcc09e40b7300
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8abef920
RBP: ffffc90010717f48 R08: dffffc0000000000 R09: fffffbfff1bfe1c6
R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90010717f58 R15: 0000000000000000
do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff214d8f749
Code: Unable to access opcode bytes at 0x7ff214d8f71f.
RSP: 002b:00007ff215b51038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff214fe5fa0 RCX: 00007ff214d8f749
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007ff215b51090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ff214fe6038 R14: 00007ff214fe5fa0 R15: 00007ffc1ca456d8
netlink: 'syz.4.6987': attribute type 6 has an invalid length.
netlink: 164 bytes leftover after parsing attributes in process `syz.4.6987'.
----------------
Code disassembly (best guess):
0: 89 f3 mov %esi,%ebx
2: 49 89 fe mov %rdi,%r14
5: 48 8b 7c 24 10 mov 0x10(%rsp),%rdi
a: e8 ed fa ff ff call 0xfffffafc
f: 66 90 xchg %ax,%ax
11: 66 90 xchg %ax,%ax
13: e8 54 ca 76 f7 call 0xf776ca6c
18: e8 cf c8 76 f7 call 0xf776c8ec
1d: fb sti
1e: 65 48 8b 05 26 fc f1 mov %gs:0x75f1fc26(%rip),%rax # 0x75f1fc4c
25: 75
26: 48 8b 70 08 mov 0x8(%rax),%rsi
* 2a: 40 f6 c6 3f test $0x3f,%sil <-- trapping instruction
2e: 74 0b je 0x3b
30: 4c 89 f7 mov %r14,%rdi
33: 5b pop %rbx
34: 41 5e pop %r14
36: e9 81 72 5d f7 jmp 0xf75d72bc
3b: 48 89 d8 mov %rbx,%rax
3e: 5b pop %rbx
3f: 41 rex.B