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.9.1127/10565 is trying to acquire lock: ffffffff8cd24160 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline] ffffffff8cd24160 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] ffffffff8cd24160 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline] ffffffff8cd24160 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992 but task is already holding lock: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 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+0x2a/0x140 kernel/sched/core.c:558 raw_spin_rq_lock kernel/sched/sched.h:1372 [inline] rq_lock kernel/sched/sched.h:1681 [inline] task_fork_fair+0x62/0x1f0 kernel/sched/fair.c:12688 sched_cgroup_fork+0x333/0x3c0 kernel/sched/core.c:4816 copy_process+0x21e4/0x3d70 kernel/fork.c:2614 kernel_clone+0x21b/0x840 kernel/fork.c:2914 user_mode_thread+0xde/0x130 kernel/fork.c:2992 rest_init+0x27/0x300 init/main.c:709 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:522 [inline] try_to_wake_up+0x60/0x1140 kernel/sched/core.c:4232 __wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:107 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x112/0x190 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6bd/0x8a0 drivers/tty/serial/8250/8250_port.c:1837 serial8250_handle_irq+0x534/0x6e0 drivers/tty/serial/8250/8250_port.c:1944 serial8250_default_handle_irq+0xb8/0x1a0 drivers/tty/serial/8250/8250_port.c:1964 serial8250_interrupt+0x9f/0x1c0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x276/0x930 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x247/0xb30 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:240 [inline] __common_interrupt+0x13b/0x230 arch/x86/kernel/irq.c:259 common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:249 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:147 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #2 (&tty->write_wait){-...}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:137 [inline] __wake_up+0xf8/0x190 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6bd/0x8a0 drivers/tty/serial/8250/8250_port.c:1837 serial8250_handle_irq+0x534/0x6e0 drivers/tty/serial/8250/8250_port.c:1944 serial8250_default_handle_irq+0xb8/0x1a0 drivers/tty/serial/8250/8250_port.c:1964 serial8250_interrupt+0x9f/0x1c0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x276/0x930 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x247/0xb30 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:240 [inline] __common_interrupt+0x13b/0x230 arch/x86/kernel/irq.c:259 common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:249 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:147 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 serial8250_console_write+0x16d/0x17a0 drivers/tty/serial/8250/8250_port.c:3433 console_emit_next_record kernel/printk/printk.c:2944 [inline] console_flush_all+0x6cd/0xd00 kernel/printk/printk.c:3000 console_unlock+0xae/0x340 kernel/printk/printk.c:3069 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341 _printk+0xd0/0x110 kernel/printk/printk.c:2366 register_console+0x91b/0xe60 kernel/printk/printk.c:3583 univ8250_console_init+0x45/0x50 drivers/tty/serial/8250/8250_core.c:717 console_init+0x17b/0x5e0 kernel/printk/printk.c:3726 start_kernel+0x2c0/0x4e0 init/main.c:1022 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #0 (console_owner){-.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 console_lock_spinning_enable kernel/printk/printk.c:1871 [inline] console_emit_next_record kernel/printk/printk.c:2938 [inline] console_flush_all+0x693/0xd00 kernel/printk/printk.c:3000 console_unlock+0xae/0x340 kernel/printk/printk.c:3069 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341 _printk+0xd0/0x110 kernel/printk/printk.c:2366 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x37e/0x4d0 lib/fault-inject.c:153 strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:212 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:307 [inline] bpf_probe_read_compat_str+0xe1/0x170 kernel/trace/bpf_trace.c:303 bpf_prog_c1796171ffc7efef+0x3d/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2197/0x44d0 kernel/sched/core.c:6696 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 __fget_light fs/file.c:-1 [inline] __fdget fs/file.c:1008 [inline] __f_unlock_pos+0x0/0x20 fs/file.c:1035 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1c1/0x250 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 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 *** 5 locks held by syz.9.1127/10565: #0: ffff888065a46fc8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xfd/0x420 kernel/trace/bpf_trace.c:2363 #3: ffffffff8cd24240 (console_lock){+.+.}-{0:0}, at: _printk+0xd0/0x110 kernel/printk/printk.c:2366 #4: ffffffff8cc0ba50 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline] #4: ffffffff8cc0ba50 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] #4: ffffffff8cc0ba50 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline] #4: ffffffff8cc0ba50 (console_srcu){....}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992 stack backtrace: CPU: 0 PID: 10565 Comm: syz.9.1127 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 console_lock_spinning_enable kernel/printk/printk.c:1871 [inline] console_emit_next_record kernel/printk/printk.c:2938 [inline] console_flush_all+0x693/0xd00 kernel/printk/printk.c:3000 console_unlock+0xae/0x340 kernel/printk/printk.c:3069 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341 _printk+0xd0/0x110 kernel/printk/printk.c:2366 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x37e/0x4d0 lib/fault-inject.c:153 strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:212 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:307 [inline] bpf_probe_read_compat_str+0xe1/0x170 kernel/trace/bpf_trace.c:303 bpf_prog_c1796171ffc7efef+0x3d/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2197/0x44d0 kernel/sched/core.c:6696 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:__f_unlock_pos+0x0/0x20 fs/file.c:1046 Code: fe ff ff 4c 89 ff e8 8f 1e e9 ff e9 a3 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 16 fe ff ff e8 75 1e e9 ff e9 0c fe ff ff <66> 0f 1f 00 53 48 89 fb e8 93 b0 91 ff 48 83 c3 60 48 89 df 5b e9 RSP: 0018:ffffc90004defe58 EFLAGS: 00000293 RAX: ffffffff81ebcfb7 RBX: ffff888065a46f03 RCX: ffff888027103c00 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff888065a46f00 RBP: ffffc90004deff10 R08: ffffffff8e4a212f R09: 1ffffffff1c94425 R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000001 R13: 0000000000000002 R14: 1ffff920009bdfd0 R15: ffff888065a46ff0 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1c1/0x250 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3fe2f8e1ff 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:00007f3fe3d86030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f3fe2f8e1ff RDX: 0000000000000001 RSI: 00007f3fe3d86090 RDI: 0000000000000008 RBP: 00007f3fe3d86090 R08: 0000000000000000 R09: 00007f3fe3d85df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f3fe31e6218 R14: 00007f3fe31e6180 R15: 00007ffd5b6e38d8 CPU: 0 PID: 10565 Comm: syz.9.1127 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 fail_dump lib/fault-inject.c:52 [inline] should_fail_ex+0x39d/0x4d0 lib/fault-inject.c:153 strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:212 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:307 [inline] bpf_probe_read_compat_str+0xe1/0x170 kernel/trace/bpf_trace.c:303 bpf_prog_c1796171ffc7efef+0x3d/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2197/0x44d0 kernel/sched/core.c:6696 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:__f_unlock_pos+0x0/0x20 fs/file.c:1046 Code: fe ff ff 4c 89 ff e8 8f 1e e9 ff e9 a3 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 16 fe ff ff e8 75 1e e9 ff e9 0c fe ff ff <66> 0f 1f 00 53 48 89 fb e8 93 b0 91 ff 48 83 c3 60 48 89 df 5b e9 RSP: 0018:ffffc90004defe58 EFLAGS: 00000293 RAX: ffffffff81ebcfb7 RBX: ffff888065a46f03 RCX: ffff888027103c00 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff888065a46f00 RBP: ffffc90004deff10 R08: ffffffff8e4a212f R09: 1ffffffff1c94425 R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000001 R13: 0000000000000002 R14: 1ffff920009bdfd0 R15: ffff888065a46ff0 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1c1/0x250 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3fe2f8e1ff 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:00007f3fe3d86030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f3fe2f8e1ff RDX: 0000000000000001 RSI: 00007f3fe3d86090 RDI: 0000000000000008 RBP: 00007f3fe3d86090 R08: 0000000000000000 R09: 00007f3fe3d85df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f3fe31e6218 R14: 00007f3fe31e6180 R15: 00007ffd5b6e38d8 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: ff 4c 89 ff decl -0x1(%rcx,%rcx,4) 4: e8 8f 1e e9 ff call 0xffe91e98 9: e9 a3 fe ff ff jmp 0xfffffeb1 e: 89 f9 mov %edi,%ecx 10: 80 e1 07 and $0x7,%cl 13: 80 c1 03 add $0x3,%cl 16: 38 c1 cmp %al,%cl 18: 0f 8c 16 fe ff ff jl 0xfffffe34 1e: e8 75 1e e9 ff call 0xffe91e98 23: e9 0c fe ff ff jmp 0xfffffe34 * 28: 66 0f 1f 00 nopw (%rax) <-- trapping instruction 2c: 53 push %rbx 2d: 48 89 fb mov %rdi,%rbx 30: e8 93 b0 91 ff call 0xff91b0c8 35: 48 83 c3 60 add $0x60,%rbx 39: 48 89 df mov %rbx,%rdi 3c: 5b pop %rbx 3d: e9 .byte 0xe9