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.3.1139/10666 is trying to acquire lock: ffffffff8df31660 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] ffffffff8df31660 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline] ffffffff8df31660 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline] ffffffff8df31660 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176 but task is already holding lock: ffff8880b883a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638 raw_spin_rq_lock kernel/sched/sched.h:1547 [inline] task_rq_lock+0xbc/0x470 kernel/sched/core.c:738 cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170 css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:951 cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6913 copy_process+0x3862/0x3c00 kernel/fork.c:2425 kernel_clone+0x21e/0x840 kernel/fork.c:2609 user_mode_thread+0xdd/0x140 kernel/fork.c:2685 rest_init+0x23/0x300 init/main.c:722 start_kernel+0x3ae/0x410 init/main.c:1111 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}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline] try_to_wake_up+0x67/0x12b0 kernel/sched/core.c:4181 __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:82 __handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203 handle_irq_event_percpu kernel/irq/handle.c:240 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257 handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:254 [inline] call_irq_handler arch/x86/kernel/irq.c:-1 [inline] __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325 common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318 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:81 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147 -> #2 (&tty->write_wait){-.-.}-{3:3}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 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:82 __handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203 handle_irq_event_percpu kernel/irq/handle.c:240 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257 handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:254 [inline] call_irq_handler arch/x86/kernel/irq.c:-1 [inline] __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325 common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318 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:81 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147 -> #1 (&port_lock_key){-.-.}-{3:3}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3301 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 _printk+0xcf/0x120 kernel/printk/printk.c:2448 register_console+0xa8b/0xf90 kernel/printk/printk.c:4099 univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:511 console_init+0x10e/0x430 kernel/printk/printk.c:4298 start_kernel+0x254/0x410 init/main.c:1048 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 console_lock_spinning_enable kernel/printk/printk.c:1897 [inline] console_emit_next_record kernel/printk/printk.c:3105 [inline] console_flush_all+0x69c/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 _printk+0xcf/0x120 kernel/printk/printk.c:2448 fail_dump lib/fault-inject.c:66 [inline] should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174 strncpy_from_user+0x36/0x290 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_user_str kernel/trace/bpf_trace.c:223 [inline] bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220 bpf_prog_c762caf419d1c004+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline] __bpf_prog_run include/linux/filter.h:721 [inline] bpf_prog_run include/linux/filter.h:728 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220 __do_trace_sched_switch include/trace/events/sched.h:220 [inline] trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x238f/0x4cc0 kernel/sched/core.c:6926 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 exit_to_user_mode_loop+0x45/0x130 kernel/entry/common.c:30 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 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.3.1139/10666: #0: ffff8880b883a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646 #1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline] #1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2118 #2: ffffffff8df316c0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2448 #3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] #3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline] #3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline] #3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176 stack backtrace: CPU: 1 UID: 0 PID: 10666 Comm: syz.3.1139 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 console_lock_spinning_enable kernel/printk/printk.c:1897 [inline] console_emit_next_record kernel/printk/printk.c:3105 [inline] console_flush_all+0x69c/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 _printk+0xcf/0x120 kernel/printk/printk.c:2448 fail_dump lib/fault-inject.c:66 [inline] should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174 strncpy_from_user+0x36/0x290 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_user_str kernel/trace/bpf_trace.c:223 [inline] bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220 bpf_prog_c762caf419d1c004+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline] __bpf_prog_run include/linux/filter.h:721 [inline] bpf_prog_run include/linux/filter.h:728 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220 __do_trace_sched_switch include/trace/events/sched.h:220 [inline] trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x238f/0x4cc0 kernel/sched/core.c:6926 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:exit_to_user_mode_loop+0x45/0x130 kernel/entry/common.c:30 Code: eb 1e e8 de 6a 9c 09 65 48 8b 04 25 08 50 6e 92 4c 8b 30 41 f7 c6 37 03 00 00 0f 84 d6 00 00 00 e8 40 92 1d 00 fb 41 f6 c6 30 <74> 05 e8 b4 73 9d 09 41 f7 c6 00 01 00 00 74 08 48 89 df e8 e3 dd RSP: 0018:ffffc900035afec0 EFLAGS: 00000202 RAX: 947273f83dcdfe00 RBX: ffffc900035aff48 RCX: 947273f83dcdfe00 RDX: 0000000000000000 RSI: ffffffff8d70e436 RDI: ffffffff8bbf08e0 RBP: ffffc900035aff38 R08: ffffffff8f7cee77 R09: 1ffffffff1ef9dce R10: dffffc0000000000 R11: fffffbfff1ef9dcf R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000080010 R15: ffff88802c93bc80 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f412938e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f412a29e030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 0000000000000006 RCX: 00007f412938e1ff RDX: 0000000000000001 RSI: 00007f412a29e090 RDI: 0000000000000006 RBP: 00007f412a29e090 R08: 0000000000000000 R09: 00007f412a29ddf7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f41295e6218 R14: 00007f41295e6180 R15: 00007ffd6de30698 CPU: 1 UID: 0 PID: 10666 Comm: syz.3.1139 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 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+0x36/0x290 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_user_str kernel/trace/bpf_trace.c:223 [inline] bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220 bpf_prog_c762caf419d1c004+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline] __bpf_prog_run include/linux/filter.h:721 [inline] bpf_prog_run include/linux/filter.h:728 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220 __do_trace_sched_switch include/trace/events/sched.h:220 [inline] trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x238f/0x4cc0 kernel/sched/core.c:6926 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:exit_to_user_mode_loop+0x45/0x130 kernel/entry/common.c:30 Code: eb 1e e8 de 6a 9c 09 65 48 8b 04 25 08 50 6e 92 4c 8b 30 41 f7 c6 37 03 00 00 0f 84 d6 00 00 00 e8 40 92 1d 00 fb 41 f6 c6 30 <74> 05 e8 b4 73 9d 09 41 f7 c6 00 01 00 00 74 08 48 89 df e8 e3 dd RSP: 0018:ffffc900035afec0 EFLAGS: 00000202 RAX: 947273f83dcdfe00 RBX: ffffc900035aff48 RCX: 947273f83dcdfe00 RDX: 0000000000000000 RSI: ffffffff8d70e436 RDI: ffffffff8bbf08e0 RBP: ffffc900035aff38 R08: ffffffff8f7cee77 R09: 1ffffffff1ef9dce R10: dffffc0000000000 R11: fffffbfff1ef9dcf R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000080010 R15: ffff88802c93bc80 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f412938e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f412a29e030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 0000000000000006 RCX: 00007f412938e1ff RDX: 0000000000000001 RSI: 00007f412a29e090 RDI: 0000000000000006 RBP: 00007f412a29e090 R08: 0000000000000000 R09: 00007f412a29ddf7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f41295e6218 R14: 00007f41295e6180 R15: 00007ffd6de30698 ---------------- Code disassembly (best guess): 0: eb 1e jmp 0x20 2: e8 de 6a 9c 09 call 0x99c6ae5 7: 65 48 8b 04 25 08 50 mov %gs:0xffffffff926e5008,%rax e: 6e 92 10: 4c 8b 30 mov (%rax),%r14 13: 41 f7 c6 37 03 00 00 test $0x337,%r14d 1a: 0f 84 d6 00 00 00 je 0xf6 20: e8 40 92 1d 00 call 0x1d9265 25: fb sti 26: 41 f6 c6 30 test $0x30,%r14b * 2a: 74 05 je 0x31 <-- trapping instruction 2c: e8 b4 73 9d 09 call 0x99d73e5 31: 41 f7 c6 00 01 00 00 test $0x100,%r14d 38: 74 08 je 0x42 3a: 48 89 df mov %rbx,%rdi 3d: e8 .byte 0xe8 3e: e3 dd jrcxz 0x1d