FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.140-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.3564/14796 is trying to acquire lock:
ffffffff8c91ecc0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8c91ecc0 (console_owner){-.-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774

but task is already holding lock:
ffff8880b8e3aa58 (&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:11888
       sched_cgroup_fork+0x32c/0x3c0 kernel/sched/core.c:4685
       copy_process+0x248b/0x4060 kernel/fork.c:2383
       kernel_clone+0x225/0x8b0 kernel/fork.c:2681
       user_mode_thread+0xda/0x130 kernel/fork.c:2757
       rest_init+0x23/0x300 init/main.c:698
       start_kernel+0x0/0x539 init/main.c:893
       start_kernel+0x490/0x539 init/main.c:1140
       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
       __sanitizer_cov_trace_cmp1+0x0/0x80
       mt_validate_nulls lib/maple_tree.c:7195 [inline]
       mt_validate+0x45ef/0x4c90 lib/maple_tree.c:7244
       validate_mm_mt+0xcd/0x420 mm/mmap.c:294
       __split_vma+0x30/0x500 mm/mmap.c:2343
       do_mas_align_munmap+0x351/0x1220 mm/mmap.c:2468
       do_mas_munmap+0x240/0x2b0 mm/mmap.c:2638
       __mmap_region mm/mmap.c:2686 [inline]
       mmap_region+0x713/0x1d30 mm/mmap.c:2904
       do_mmap+0x894/0xf30 mm/mmap.c:1424
       vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
       ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1470
       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

-> #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:3433
       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:1076
       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_compat_str kernel/trace/bpf_trace.c:310 [inline]
       bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
       bpf_prog_34c20d315800ee20+0x38/0x3f
       bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline]
       __bpf_prog_run include/linux/filter.h:596 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
       bpf_trace_run2+0x30a/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+0xe96/0x40d0 kernel/sched/core.c:6561
       schedule+0xb9/0x180 kernel/sched/core.c:6637
       schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
       __mutex_lock_common kernel/locking/mutex.c:679 [inline]
       __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
       ip_rt_ioctl+0xdb/0x1120 net/ipv4/fib_frontend.c:630
       inet_ioctl+0x364/0x400 net/ipv4/af_inet.c:978
       sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204
       sock_ioctl+0x4ed/0x6e0 net/socket.c:1321
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
       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

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 ***

4 locks held by syz.3.3564/14796:
 #0: ffffffff8db34428 (rtnl_mutex){+.+.}-{3:3}, at: ip_rt_ioctl+0xdb/0x1120 net/ipv4/fib_frontend.c:630
 #1: ffff8880b8e3aa58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #2: ffffffff8c92ab20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #2: ffffffff8c92ab20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #2: ffffffff8c92ab20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #2: ffffffff8c92ab20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324
 #3: ffffffff8c91eda0 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328

stack backtrace:
CPU: 0 PID: 14796 Comm: syz.3.3564 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_34c20d315800ee20+0x38/0x3f
 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline]
 __bpf_prog_run include/linux/filter.h:596 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run2+0x30a/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+0xe96/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 ip_rt_ioctl+0xdb/0x1120 net/ipv4/fib_frontend.c:630
 inet_ioctl+0x364/0x400 net/ipv4/af_inet.c:978
 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 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
RIP: 0033:0x7efe41d8e969
Code: Unable to access opcode bytes at 0x7efe41d8e93f.
RSP: 002b:00007efe42c38038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007efe41fb5fa0 RCX: 00007efe41d8e969
RDX: 0000200000000100 RSI: 000000000000890b RDI: 0000000000000003
RBP: 00007efe42c38090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007efe41fb5fa0 R15: 00007ffdd3f98b28
 </TASK>
CPU: 0 PID: 14796 Comm: syz.3.3564 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_34c20d315800ee20+0x38/0x3f
 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline]
 __bpf_prog_run include/linux/filter.h:596 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run2+0x30a/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+0xe96/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 ip_rt_ioctl+0xdb/0x1120 net/ipv4/fib_frontend.c:630
 inet_ioctl+0x364/0x400 net/ipv4/af_inet.c:978
 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 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
RIP: 0033:0x7efe41d8e969
Code: Unable to access opcode bytes at 0x7efe41d8e93f.
RSP: 002b:00007efe42c38038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007efe41fb5fa0 RCX: 00007efe41d8e969
RDX: 0000200000000100 RSI: 000000000000890b RDI: 0000000000000003
RBP: 00007efe42c38090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007efe41fb5fa0 R15: 00007ffdd3f98b28
 </TASK>