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.1.959/7510 is trying to acquire lock: ffffffff8c91f2e0 (console_owner){..-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] ffffffff8c91f2e0 (console_owner){..-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774 but task is already holding lock: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545 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:11901 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:710 start_kernel+0x0/0x539 init/main.c:905 start_kernel+0x490/0x539 init/main.c:1152 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 arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] rcu_is_watching+0x56/0xa0 kernel/rcu/tree.c:721 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xd4/0x910 kernel/locking/lockdep.c:5673 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] zap_pte_range mm/memory.c:1435 [inline] zap_pmd_range mm/memory.c:1574 [inline] zap_pud_range mm/memory.c:1603 [inline] zap_p4d_range mm/memory.c:1624 [inline] unmap_page_range+0x1924/0x2500 mm/memory.c:1645 unmap_vmas+0x22c/0x330 mm/memory.c:1730 exit_mmap+0x1cc/0x8e0 mm/mmap.c:3250 __mmput+0x118/0x3c0 kernel/fork.c:1200 exit_mm+0x1e6/0x2c0 kernel/exit.c:565 do_exit+0x8c1/0x2400 kernel/exit.c:867 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 __do_sys_exit_group kernel/exit.c:1033 [inline] __se_sys_exit_group kernel/exit.c:1031 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031 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 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_write+0x68a/0x910 drivers/tty/serial/serial_core.c:602 process_output_block drivers/tty/n_tty.c:586 [inline] n_tty_write+0xd1a/0x11c0 drivers/tty/n_tty.c:2377 do_tty_write drivers/tty/tty_io.c:1018 [inline] file_tty_write+0x4dd/0x860 drivers/tty/tty_io.c:1089 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x44c/0x960 fs/read_write.c:584 ksys_write+0x143/0x240 fs/read_write.c:637 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 -> #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:3432 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:1088 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:1012 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run4+0x1f5/0x420 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_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 memset+0x1/0x40 mm/kasan/shadow.c:43 ___sys_recvmsg+0xc6/0x510 net/socket.c:2771 do_recvmmsg+0x359/0x7d0 net/socket.c:2874 __sys_recvmmsg net/socket.c:2953 [inline] __do_sys_recvmmsg net/socket.c:2976 [inline] __se_sys_recvmmsg net/socket.c:2969 [inline] __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2969 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 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.1.959/7510: #0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545 #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xf9/0x420 kernel/trace/bpf_trace.c:2326 #2: ffffffff8c91f3c0 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328 stack backtrace: CPU: 1 PID: 7510 Comm: syz.1.959 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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:1012 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run4+0x1f5/0x420 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_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:memset+0x1/0x40 mm/kasan/shadow.c:43 Code: 08 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 31 d2 e9 a3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 90 ec ff ff 55 <41> 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 RSP: 0018:ffffc9000d777a70 EFLAGS: 00000246 RAX: ffffffff8812bf87 RBX: ffffc9000d777b40 RCX: ffff88802ba29dc0 RDX: 0000000000000080 RSI: 0000000000000000 RDI: ffffc9000d777b40 RBP: ffffc9000d777c70 R08: 0000000000000000 R09: fffffbfff1bfe1c6 R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: 0000000000002122 R13: dffffc0000000000 R14: ffffc9000d777be0 R15: 1ffff92001aeef58 ___sys_recvmsg+0xc6/0x510 net/socket.c:2771 do_recvmmsg+0x359/0x7d0 net/socket.c:2874 __sys_recvmmsg net/socket.c:2953 [inline] __do_sys_recvmmsg net/socket.c:2976 [inline] __se_sys_recvmmsg net/socket.c:2969 [inline] __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2969 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 RIP: 0033:0x7f3462f8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3463d63038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f34631e6090 RCX: 00007f3462f8f749 RDX: 00000000040001af RSI: 0000200000000a40 RDI: 0000000000000009 RBP: 00007f3463d63090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000012122 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f34631e6128 R14: 00007f34631e6090 R15: 00007ffc1a8808e8 CPU: 1 PID: 7510 Comm: syz.1.959 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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:1012 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run4+0x1f5/0x420 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_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:memset+0x1/0x40 mm/kasan/shadow.c:43 Code: 08 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 31 d2 e9 a3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 90 ec ff ff 55 <41> 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 RSP: 0018:ffffc9000d777a70 EFLAGS: 00000246 RAX: ffffffff8812bf87 RBX: ffffc9000d777b40 RCX: ffff88802ba29dc0 RDX: 0000000000000080 RSI: 0000000000000000 RDI: ffffc9000d777b40 RBP: ffffc9000d777c70 R08: 0000000000000000 R09: fffffbfff1bfe1c6 R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: 0000000000002122 R13: dffffc0000000000 R14: ffffc9000d777be0 R15: 1ffff92001aeef58 ___sys_recvmsg+0xc6/0x510 net/socket.c:2771 do_recvmmsg+0x359/0x7d0 net/socket.c:2874 __sys_recvmmsg net/socket.c:2953 [inline] __do_sys_recvmmsg net/socket.c:2976 [inline] __se_sys_recvmmsg net/socket.c:2969 [inline] __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2969 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 RIP: 0033:0x7f3462f8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3463d63038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f34631e6090 RCX: 00007f3462f8f749 RDX: 00000000040001af RSI: 0000200000000a40 RDI: 0000000000000009 RBP: 00007f3463d63090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000012122 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f34631e6128 R14: 00007f34631e6090 R15: 00007ffc1a8808e8 ---------------- Code disassembly (best guess): 0: 08 31 or %dh,(%rcx) 2: ed in (%dx),%eax 3: eb d7 jmp 0xffffffdc 5: 00 00 add %al,(%rax) 7: cc int3 8: cc int3 9: 89 f6 mov %esi,%esi b: 48 8b 0c 24 mov (%rsp),%rcx f: 31 d2 xor %edx,%edx 11: e9 a3 ec ff ff jmp 0xffffecb9 16: 0f 1f 00 nopl (%rax) 19: 89 f6 mov %esi,%esi 1b: 48 8b 0c 24 mov (%rsp),%rcx 1f: ba 01 00 00 00 mov $0x1,%edx 24: e9 90 ec ff ff jmp 0xffffecb9 29: 55 push %rbp * 2a: 41 56 push %r14 <-- trapping instruction 2c: 53 push %rbx 2d: 48 89 d3 mov %rdx,%rbx 30: 89 f5 mov %esi,%ebp 32: 49 89 fe mov %rdi,%r14 35: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx 3a: 48 89 d6 mov %rdx,%rsi 3d: ba .byte 0xba 3e: 01 00 add %eax,(%rax)