FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.6.2568/23923 is trying to acquire lock:
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:317 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3194 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3291

but task is already holding lock:
ffff8880b863abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655

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+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
       raw_spin_rq_lock kernel/sched/sched.h:1613 [inline]
       _task_rq_lock+0xbc/0x470 kernel/sched/core.c:747
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:948
       cgroup_post_fork+0x1ef/0x7a0 kernel/cgroup/cgroup.c:6910
       copy_process+0x385e/0x3ba0 kernel/fork.c:2462
       kernel_clone+0x21e/0x820 kernel/fork.c:2648
       user_mode_thread+0xdd/0x140 kernel/fork.c:2724
       rest_init+0x23/0x300 init/main.c:725
       start_kernel+0x386/0x3d0 init/main.c:1210
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:573 [inline]
       try_to_wake_up+0x67/0x12c0 kernel/sched/core.c:4129
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x217/0x970 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
       generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
       handle_irq arch/x86/kernel/irq.c:262 [inline]
       call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:333
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:326
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       __sanitizer_cov_trace_const_cmp4+0x0/0x90 kernel/kcov.c:309
       folio_get include/linux/mm.h:1575 [inline]
       copy_present_ptes mm/memory.c:1158 [inline]
       copy_pte_range mm/memory.c:1304 [inline]
       copy_pmd_range+0x9fd/0x7e00 mm/memory.c:1392
       copy_pud_range mm/memory.c:1429 [inline]
       copy_p4d_range mm/memory.c:1453 [inline]
       copy_page_range+0xb88/0x11d0 mm/memory.c:1535
       dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827
       dup_mm kernel/fork.c:1529 [inline]
       copy_mm+0x13c/0x4b0 kernel/fork.c:1581
       copy_process+0x1812/0x3ba0 kernel/fork.c:2218
       kernel_clone+0x21e/0x820 kernel/fork.c:2648
       __do_sys_clone kernel/fork.c:2789 [inline]
       __se_sys_clone kernel/fork.c:2773 [inline]
       __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2773
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       __wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x217/0x970 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
       generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
       handle_irq arch/x86/kernel/irq.c:262 [inline]
       call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:333
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:326
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
       pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:62
       arch_safe_halt arch/x86/kernel/process.c:766 [inline]
       default_idle+0x9/0x20 arch/x86/kernel/process.c:767
       default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:191 [inline]
       do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
       rest_init+0x2de/0x300 init/main.c:760
       start_kernel+0x386/0x3d0 init/main.c:1210
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #1 (&port_lock_key){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
       serial8250_console_write+0x155/0x1b60 drivers/tty/serial/8250/8250_port.c:3301
       console_emit_next_record kernel/printk/printk.c:3131 [inline]
       console_flush_one_record kernel/printk/printk.c:3217 [inline]
       console_flush_all+0x713/0xb00 kernel/printk/printk.c:3291
       __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
       vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
       _printk+0xcf/0x120 kernel/printk/printk.c:2453
       register_console+0xa8b/0xf90 kernel/printk/printk.c:4172
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:515
       console_init+0xfc/0x3f0 kernel/printk/printk.c:4371
       start_kernel+0x22c/0x3d0 init/main.c:1147
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #0 (console_owner){-.-.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
       console_emit_next_record kernel/printk/printk.c:3125 [inline]
       console_flush_one_record kernel/printk/printk.c:3217 [inline]
       console_flush_all+0x6bc/0xb00 kernel/printk/printk.c:3291
       __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
       vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
       _printk+0xcf/0x120 kernel/printk/printk.c:2453
       fail_dump lib/fault-inject.c:66 [inline]
       should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
       strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
       bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
       bpf_prog_121d723b3c6e0163+0x49/0x4f
       bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
       __bpf_prog_run include/linux/filter.h:723 [inline]
       bpf_prog_run include/linux/filter.h:730 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
       bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
       __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
       __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
       trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
       switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
       context_switch kernel/sched/core.c:5269 [inline]
       __schedule+0x101b/0x5030 kernel/sched/core.c:6902
       preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7086
       preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
       lru_add_drain+0x22e/0x3e0 mm/swap.c:738
       __lru_add_drain_all+0x5d/0x5e0 mm/swap.c:838
       do_mbind mm/mempolicy.c:1526 [inline]
       kernel_mbind mm/mempolicy.c:1752 [inline]
       __do_sys_mbind mm/mempolicy.c:1826 [inline]
       __se_sys_mbind+0x5fc/0xc40 mm/mempolicy.c:1822
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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.6.2568/23923:
 #0: ffff8880b863abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655
 #1: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #1: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #1: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #1: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4c0 kernel/trace/bpf_trace.c:2116
 #2: ffffffff8e138be0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2453
 #3: ffffffff8e020498 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:317 [inline]
 #3: ffffffff8e020498 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #3: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #3: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3194 [inline]
 #3: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3291

stack backtrace:
CPU: 0 UID: 0 PID: 23923 Comm: syz.6.2568 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
 console_emit_next_record kernel/printk/printk.c:3125 [inline]
 console_flush_one_record kernel/printk/printk.c:3217 [inline]
 console_flush_all+0x6bc/0xb00 kernel/printk/printk.c:3291
 __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
 _printk+0xcf/0x120 kernel/printk/printk.c:2453
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_121d723b3c6e0163+0x49/0x4f
 bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
 __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
 trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
 switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5269 [inline]
 __schedule+0x101b/0x5030 kernel/sched/core.c:6902
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7086
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 lru_add_drain+0x22e/0x3e0 mm/swap.c:738
 __lru_add_drain_all+0x5d/0x5e0 mm/swap.c:838
 do_mbind mm/mempolicy.c:1526 [inline]
 kernel_mbind mm/mempolicy.c:1752 [inline]
 __do_sys_mbind mm/mempolicy.c:1826 [inline]
 __se_sys_mbind+0x5fc/0xc40 mm/mempolicy.c:1822
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7adc18f749
Code: Unable to access opcode bytes at 0x7f7adc18f71f.
RSP: 002b:00007f7ada3f6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
RAX: ffffffffffffffda RBX: 00007f7adc3e6180 RCX: 00007f7adc18f749
RDX: 0000000000000000 RSI: 0100000000004000 RDI: 00002000005b4000
RBP: 00007f7ada3f6090 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7adc3e6218 R14: 00007f7adc3e6180 R15: 00007ffdfa3276e8
 </TASK>
CPU: 0 UID: 0 PID: 23923 Comm: syz.6.2568 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x414/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_121d723b3c6e0163+0x49/0x4f
 bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
 __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
 trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
 switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5269 [inline]
 __schedule+0x101b/0x5030 kernel/sched/core.c:6902
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7086
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 lru_add_drain+0x22e/0x3e0 mm/swap.c:738
 __lru_add_drain_all+0x5d/0x5e0 mm/swap.c:838
 do_mbind mm/mempolicy.c:1526 [inline]
 kernel_mbind mm/mempolicy.c:1752 [inline]
 __do_sys_mbind mm/mempolicy.c:1826 [inline]
 __se_sys_mbind+0x5fc/0xc40 mm/mempolicy.c:1822
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7adc18f749
Code: Unable to access opcode bytes at 0x7f7adc18f71f.
RSP: 002b:00007f7ada3f6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
RAX: ffffffffffffffda RBX: 00007f7adc3e6180 RCX: 00007f7adc18f749
RDX: 0000000000000000 RSI: 0100000000004000 RDI: 00002000005b4000
RBP: 00007f7ada3f6090 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7adc3e6218 R14: 00007f7adc3e6180 R15: 00007ffdfa3276e8
 </TASK>