FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.147-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.11187/2923 is trying to acquire lock:
ffffffff8cb1efc0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8cb1efc0 (console_owner){-.-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774

but task is already holding lock:
ffff8880b8e3aa98 (&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+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: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
       memset+0x22/0x40 mm/kasan/shadow.c:44
       unwind_next_frame+0xb8a/0x20b0 arch/x86/kernel/unwind_orc.c:546
       __unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:717
       unwind_start arch/x86/include/asm/unwind.h:64 [inline]
       arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
       stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
       kasan_save_stack mm/kasan/common.c:45 [inline]
       kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
       __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:328
       kasan_slab_alloc include/linux/kasan.h:201 [inline]
       slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
       slab_alloc_node mm/slub.c:3398 [inline]
       slab_alloc mm/slub.c:3406 [inline]
       __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
       kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3422
       vm_area_dup+0x23/0x1a0 kernel/fork.c:467
       dup_mmap kernel/fork.c:646 [inline]
       dup_mm kernel/fork.c:1541 [inline]
       copy_mm+0xa7e/0x15c0 kernel/fork.c:1590
       copy_process+0x1953/0x4020 kernel/fork.c:2351
       kernel_clone+0x225/0x8b0 kernel/fork.c:2757
       __do_sys_clone kernel/fork.c:2898 [inline]
       __se_sys_clone kernel/fork.c:2882 [inline]
       __x64_sys_clone+0x17c/0x1d0 kernel/fork.c:2882
       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
       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

-> #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_c1796171ffc7efef+0x35/0x37
       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_run4+0x371/0x420 kernel/trace/bpf_trace.c:2326
       __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
       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
       exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
       irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
       asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691

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.1.11187/2923:
 #0: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #1: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #1: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xf9/0x420 kernel/trace/bpf_trace.c:2326
 #2: ffffffff8cb1f0a0 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328

stack backtrace:
CPU: 0 PID: 2923 Comm: syz.1.11187 Not tainted 6.1.147-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_c1796171ffc7efef+0x35/0x37
 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_run4+0x371/0x420 kernel/trace/bpf_trace.c:2326
 __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
 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:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 72 66 a8 08 65 48 8b 05 0a 9f 94 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 75 52 19 00 fb 41 f6 c6 08 <74> 05 e8 59 ee b0 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 28 40
RSP: 0000:ffffc900039c7f10 EFLAGS: 00000202
RAX: a3f0d5e01636d200 RBX: ffffc900039c7f58 RCX: a3f0d5e01636d200
RDX: dffffc0000000000 RSI: ffffffff8a8c0460 RDI: ffffffff8adef320
RBP: 0000000000000000 R08: ffffffff8f9f2008 R09: ffffffff8f9f2018
R10: ffffffff8f9f2010 R11: ffffffff8f9f2003 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff88802fbc8000
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fd28b855c5a
Code: 80 3d ad fa e8 00 00 0f 84 9b 00 00 00 53 48 89 fb 48 85 ff 74 1a 80 3d 6b c4 35 00 00 75 33 48 8b 43 10 48 c7 00 00 00 00 00 <c6> 43 38 00 5b c3 64 48 8b 1c 25 c0 fe ff ff 48 85 db 0f 84 85 00
RSP: 002b:00007fd28c810050 EFLAGS: 00000246
RAX: 00007fd28a9fd000 RBX: 00007fd28bbb6118 RCX: 0000000000000000
RDX: 00007fd28c810090 RSI: 00007fd28c810090 RDI: 00007fd28bbb6118
RBP: 00007fd28c810090 R08: 0000000000000000 R09: 00007fd28c80fdf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fd28bbb6080 R15: 00007ffd4f3061b8
 </TASK>
CPU: 0 PID: 2923 Comm: syz.1.11187 Not tainted 6.1.147-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_c1796171ffc7efef+0x35/0x37
 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_run4+0x371/0x420 kernel/trace/bpf_trace.c:2326
 __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
 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:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 72 66 a8 08 65 48 8b 05 0a 9f 94 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 75 52 19 00 fb 41 f6 c6 08 <74> 05 e8 59 ee b0 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 28 40
RSP: 0000:ffffc900039c7f10 EFLAGS: 00000202
RAX: a3f0d5e01636d200 RBX: ffffc900039c7f58 RCX: a3f0d5e01636d200
RDX: dffffc0000000000 RSI: ffffffff8a8c0460 RDI: ffffffff8adef320
RBP: 0000000000000000 R08: ffffffff8f9f2008 R09: ffffffff8f9f2018
R10: ffffffff8f9f2010 R11: ffffffff8f9f2003 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff88802fbc8000
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fd28b855c5a
Code: 80 3d ad fa e8 00 00 0f 84 9b 00 00 00 53 48 89 fb 48 85 ff 74 1a 80 3d 6b c4 35 00 00 75 33 48 8b 43 10 48 c7 00 00 00 00 00 <c6> 43 38 00 5b c3 64 48 8b 1c 25 c0 fe ff ff 48 85 db 0f 84 85 00
RSP: 002b:00007fd28c810050 EFLAGS: 00000246
RAX: 00007fd28a9fd000 RBX: 00007fd28bbb6118 RCX: 0000000000000000
RDX: 00007fd28c810090 RSI: 00007fd28c810090 RDI: 00007fd28bbb6118
RBP: 00007fd28c810090 R08: 0000000000000000 R09: 00007fd28c80fdf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fd28bbb6080 R15: 00007ffd4f3061b8
 </TASK>
----------------
Code disassembly (best guess):
   0:	fb                   	sti
   1:	eb 1d                	jmp    0x20
   3:	e8 72 66 a8 08       	call   0x8a8667a
   8:	65 48 8b 05 0a 9f 94 	mov    %gs:0x7e949f0a(%rip),%rax        # 0x7e949f1a
   f:	7e
  10:	4c 8b 30             	mov    (%rax),%r14
  13:	41 f7 c6 0e 30 02 00 	test   $0x2300e,%r14d
  1a:	0f 84 c4 00 00 00    	je     0xe4
  20:	e8 75 52 19 00       	call   0x19529a
  25:	fb                   	sti
  26:	41 f6 c6 08          	test   $0x8,%r14b
* 2a:	74 05                	je     0x31 <-- trapping instruction
  2c:	e8 59 ee b0 08       	call   0x8b0ee8a
  31:	41 f7 c6 00 10 00 00 	test   $0x1000,%r14d
  38:	74 08                	je     0x42
  3a:	48 89 df             	mov    %rbx,%rdi
  3d:	e8                   	.byte 0xe8
  3e:	28                   	.byte 0x28
  3f:	40                   	rex