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.0.2413/15476 is trying to acquire lock: ffffffff8e2d1680 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x61/0x80 kernel/printk/printk.c:1897 but task is already holding lock: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638 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+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638 raw_spin_rq_lock kernel/sched/sched.h:1546 [inline] task_rq_lock+0xcf/0x490 kernel/sched/core.c:738 cgroup_move_task+0x81/0x2a0 kernel/sched/psi.c:1170 css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:951 cgroup_post_fork+0x201/0x9d0 kernel/cgroup/cgroup.c:6913 copy_process+0x602d/0x76a0 kernel/fork.c:2425 kernel_clone+0xfc/0x930 kernel/fork.c:2609 user_mode_thread+0xc8/0x110 kernel/fork.c:2685 rest_init+0x23/0x2b0 init/main.c:722 start_kernel+0x3f6/0x4e0 init/main.c:1111 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 -> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline] try_to_wake_up+0xb7/0x1870 kernel/sched/core.c:4181 __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:108 __wake_up_common_lock kernel/sched/wait.c:125 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:146 tty_port_default_wakeup+0x47/0x60 drivers/tty/tty_port.c:67 serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1719 serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1827 serial8250_default_handle_irq+0x9e/0x270 drivers/tty/serial/8250/8250_port.c:1846 serial8250_interrupt+0xf8/0x1d0 drivers/tty/serial/8250/8250_core.c:82 __handle_irq_event_percpu+0x236/0x920 kernel/irq/handle.c:203 handle_irq_event_percpu kernel/irq/handle.c:240 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:257 handle_edge_irq+0x3ca/0x9e0 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:310 [inline] __common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325 common_interrupt+0xba/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+0xf/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+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148 -> #2 (&tty->write_wait){-.-.}-{3:3}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:124 [inline] __wake_up+0x1c/0x60 kernel/sched/wait.c:146 tty_port_default_wakeup+0x47/0x60 drivers/tty/tty_port.c:67 serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1719 serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1827 serial8250_default_handle_irq+0x9e/0x270 drivers/tty/serial/8250/8250_port.c:1846 serial8250_interrupt+0xf8/0x1d0 drivers/tty/serial/8250/8250_core.c:82 __handle_irq_event_percpu+0x236/0x920 kernel/irq/handle.c:203 handle_irq_event_percpu kernel/irq/handle.c:240 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:257 handle_edge_irq+0x3ca/0x9e0 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:310 [inline] __common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325 common_interrupt+0xba/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+0xf/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+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148 -> #1 (&port_lock_key){-.-.}-{3:3}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_console_write+0x181/0x1890 drivers/tty/serial/8250/8250_port.c:3301 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3298 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423 _printk+0xc7/0x100 kernel/printk/printk.c:2448 register_console+0xc2d/0x11b0 kernel/printk/printk.c:4099 univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:511 console_init+0x152/0x680 kernel/printk/printk.c:4298 start_kernel+0x29f/0x4e0 init/main.c:1048 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 -> #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+0x126f/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1897 console_emit_next_record kernel/printk/printk.c:3105 [inline] console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3298 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423 _printk+0xc7/0x100 kernel/printk/printk.c:2448 fail_dump lib/fault-inject.c:66 [inline] should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174 strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x7f/0x180 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+0xe8/0x180 kernel/trace/bpf_trace.c:305 bpf_prog_573c5a647519ba93+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+0x252/0x5b0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x145/0x190 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+0x183b/0x5de0 kernel/sched/core.c:6926 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 __f_unlock_pos+0x4/0x20 fs/file.c:1238 fdput_pos include/linux/file.h:79 [inline] class_fd_pos_destructor include/linux/file.h:85 [inline] ksys_write+0x190/0x250 fs/read_write.c:729 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 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 *** 5 locks held by syz.0.2413/15476: #0: ffff888034c8fb38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232 #1: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638 #2: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #2: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline] #2: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x1d5/0x5b0 kernel/trace/bpf_trace.c:2118 #3: ffffffff8e3b1ac0 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2448 #4: ffffffff8e3b1b30 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] #4: ffffffff8e3b1b30 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline] #4: ffffffff8e3b1b30 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline] #4: ffffffff8e3b1b30 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3176 stack backtrace: CPU: 0 UID: 0 PID: 15476 Comm: syz.0.2413 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043 check_noncircular+0x14c/0x170 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+0x126f/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1897 console_emit_next_record kernel/printk/printk.c:3105 [inline] console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3298 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423 _printk+0xc7/0x100 kernel/printk/printk.c:2448 fail_dump lib/fault-inject.c:66 [inline] should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174 strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x7f/0x180 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+0xe8/0x180 kernel/trace/bpf_trace.c:305 bpf_prog_573c5a647519ba93+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+0x252/0x5b0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x145/0x190 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+0x183b/0x5de0 kernel/sched/core.c:6926 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__f_unlock_pos+0x4/0x20 fs/file.c:1238 Code: ff e9 fb fe ff ff e8 6b 48 e4 ff e9 15 ff ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 <53> 48 89 fb e8 d3 c0 7b ff 48 8d bb 90 00 00 00 5b e9 76 f9 25 09 RSP: 0018:ffffc9000c387e78 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff888034c8fa43 RCX: ffffffff8237e00e RDX: ffff88807b7c8000 RSI: ffffffff8237e018 RDI: ffff888034c8fa40 RBP: ffff888034c8fa40 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000001 R12: 1ffff92001870fd0 R13: 0000000000000001 R14: 0000000000000002 R15: 0000000000000000 fdput_pos include/linux/file.h:79 [inline] class_fd_pos_destructor include/linux/file.h:85 [inline] ksys_write+0x190/0x250 fs/read_write.c:729 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f1af8d97f 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:00007f2f1bea6030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f2f1af8d97f RDX: 0000000000000001 RSI: 00007f2f1bea6090 RDI: 0000000000000008 RBP: 00007f2f1bea6090 R08: 0000000000000000 R09: 00007f2f1bea5df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f2f1b1e6218 R14: 00007f2f1b1e6180 R15: 00007ffe33f57178 CPU: 0 UID: 0 PID: 15476 Comm: syz.0.2413 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x512/0x640 lib/fault-inject.c:174 strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x7f/0x180 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+0xe8/0x180 kernel/trace/bpf_trace.c:305 bpf_prog_573c5a647519ba93+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+0x252/0x5b0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x145/0x190 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+0x183b/0x5de0 kernel/sched/core.c:6926 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__f_unlock_pos+0x4/0x20 fs/file.c:1238 Code: ff e9 fb fe ff ff e8 6b 48 e4 ff e9 15 ff ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 <53> 48 89 fb e8 d3 c0 7b ff 48 8d bb 90 00 00 00 5b e9 76 f9 25 09 RSP: 0018:ffffc9000c387e78 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff888034c8fa43 RCX: ffffffff8237e00e RDX: ffff88807b7c8000 RSI: ffffffff8237e018 RDI: ffff888034c8fa40 RBP: ffff888034c8fa40 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000001 R12: 1ffff92001870fd0 R13: 0000000000000001 R14: 0000000000000002 R15: 0000000000000000 fdput_pos include/linux/file.h:79 [inline] class_fd_pos_destructor include/linux/file.h:85 [inline] ksys_write+0x190/0x250 fs/read_write.c:729 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f1af8d97f 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:00007f2f1bea6030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f2f1af8d97f RDX: 0000000000000001 RSI: 00007f2f1bea6090 RDI: 0000000000000008 RBP: 00007f2f1bea6090 R08: 0000000000000000 R09: 00007f2f1bea5df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f2f1b1e6218 R14: 00007f2f1b1e6180 R15: 00007ffe33f57178 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e9 fb fe ff ff jmp 0xffffff00 5: e8 6b 48 e4 ff call 0xffe44875 a: e9 15 ff ff ff jmp 0xffffff24 f: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 0f 1f 40 d6 nopl -0x2a(%rax) * 29: 53 push %rbx <-- trapping instruction 2a: 48 89 fb mov %rdi,%rbx 2d: e8 d3 c0 7b ff call 0xff7bc105 32: 48 8d bb 90 00 00 00 lea 0x90(%rbx),%rdi 39: 5b pop %rbx 3a: e9 76 f9 25 09 jmp 0x925f9b5