FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 ====================================================== WARNING: possible circular locking dependency detected 6.1.147-syzkaller #0 Not tainted ------------------------------------------------------ syz.0.5536/26416 is trying to acquire lock: ffffffff8cb1efc0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] ffffffff8cb1efc0 (console_owner){-.-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774 but task is already holding lock: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 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:11888 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:698 start_kernel+0x0/0x539 init/main.c:893 start_kernel+0x490/0x539 init/main.c:1140 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+0x59/0xd0 arch/x86/kernel/irq.c:242 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682 -> #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:3433 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:1076 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_3ba3839c117aeaac+0x38/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5229 [inline] __schedule+0xe99/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 security_inode_need_killpriv+0x3e/0x90 security/security.c:1436 dentry_needs_remove_privs fs/inode.c:2054 [inline] __file_remove_privs+0x225/0x5b0 fs/inode.c:2085 __generic_file_write_iter+0xc1/0x430 mm/filemap.c:3919 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006 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 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 *** 6 locks held by syz.0.5536/26416: #0: ffff8880594ce368 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1040 #1: ffff888073098460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580 #2: ffff8880786e41b0 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #2: ffff8880786e41b0 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: generic_file_write_iter+0x7f/0x2e0 mm/filemap.c:4003 #3: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #4: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 #5: ffffffff8cb1f0a0 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328 stack backtrace: CPU: 0 PID: 26416 Comm: syz.0.5536 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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_3ba3839c117aeaac+0x38/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5229 [inline] __schedule+0xe99/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:security_inode_need_killpriv+0x3e/0x90 security/security.c:1436 Code: e8 b7 c9 be fd 49 c7 c6 50 1b 5e 8c 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1a e6 0e fe 4d 8b 36 4d 85 f6 74 2b <4d> 8d 7e 18 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 RSP: 0018:ffffc900049efaf8 EFLAGS: 00000286 RAX: 1ffffffff18bc36a RBX: ffff8880717dd1a0 RCX: ffff8880274d9dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880717dd1a0 RBP: ffffc900049efc50 R08: dffffc0000000000 R09: ffffed100f0dc82a R10: ffffed100f0dc82a R11: 1ffff1100f0dc829 R12: dffffc0000000000 R13: 1ffff9200093df6c R14: ffffffff8c5e1748 R15: dffffc0000000000 dentry_needs_remove_privs fs/inode.c:2054 [inline] __file_remove_privs+0x225/0x5b0 fs/inode.c:2085 __generic_file_write_iter+0xc1/0x430 mm/filemap.c:3919 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006 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 RIP: 0033:0x7fc59fd8ebe9 Code: Unable to access opcode bytes at 0x7fc59fd8ebbf. RSP: 002b:00007fc5a0b7b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc59ffb5fa0 RCX: 00007fc59fd8ebe9 RDX: 0000000000032600 RSI: 0000200000000300 RDI: 0000000000000007 RBP: 00007fc5a0b7b090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fc59ffb6038 R14: 00007fc59ffb5fa0 R15: 00007ffef41007e8 CPU: 0 PID: 26416 Comm: syz.0.5536 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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_3ba3839c117aeaac+0x38/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5229 [inline] __schedule+0xe99/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:security_inode_need_killpriv+0x3e/0x90 security/security.c:1436 Code: e8 b7 c9 be fd 49 c7 c6 50 1b 5e 8c 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1a e6 0e fe 4d 8b 36 4d 85 f6 74 2b <4d> 8d 7e 18 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 RSP: 0018:ffffc900049efaf8 EFLAGS: 00000286 RAX: 1ffffffff18bc36a RBX: ffff8880717dd1a0 RCX: ffff8880274d9dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880717dd1a0 RBP: ffffc900049efc50 R08: dffffc0000000000 R09: ffffed100f0dc82a R10: ffffed100f0dc82a R11: 1ffff1100f0dc829 R12: dffffc0000000000 R13: 1ffff9200093df6c R14: ffffffff8c5e1748 R15: dffffc0000000000 dentry_needs_remove_privs fs/inode.c:2054 [inline] __file_remove_privs+0x225/0x5b0 fs/inode.c:2085 __generic_file_write_iter+0xc1/0x430 mm/filemap.c:3919 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006 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 RIP: 0033:0x7fc59fd8ebe9 Code: Unable to access opcode bytes at 0x7fc59fd8ebbf. RSP: 002b:00007fc5a0b7b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc59ffb5fa0 RCX: 00007fc59fd8ebe9 RDX: 0000000000032600 RSI: 0000200000000300 RDI: 0000000000000007 RBP: 00007fc5a0b7b090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fc59ffb6038 R14: 00007fc59ffb5fa0 R15: 00007ffef41007e8 ---------------- Code disassembly (best guess): 0: e8 b7 c9 be fd call 0xfdbec9bc 5: 49 c7 c6 50 1b 5e 8c mov $0xffffffff8c5e1b50,%r14 c: 4c 89 f0 mov %r14,%rax f: 48 c1 e8 03 shr $0x3,%rax 13: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) 18: 74 08 je 0x22 1a: 4c 89 f7 mov %r14,%rdi 1d: e8 1a e6 0e fe call 0xfe0ee63c 22: 4d 8b 36 mov (%r14),%r14 25: 4d 85 f6 test %r14,%r14 28: 74 2b je 0x55 * 2a: 4d 8d 7e 18 lea 0x18(%r14),%r15 <-- trapping instruction 2e: 4c 89 f8 mov %r15,%rax 31: 48 c1 e8 03 shr $0x3,%rax 35: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) 3a: 74 08 je 0x44 3c: 4c 89 ff mov %r15,%rdi 3f: e8 .byte 0xe8