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.5.1922/14653 is trying to acquire lock: ffffffff8cb1ee60 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] ffffffff8cb1ee60 (console_owner){-.-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774 but task is already holding lock: ffff8880b8f3aad8 (&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: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 jhash2 include/linux/jhash.h:129 [inline] hash_stack lib/stackdepot.c:276 [inline] __stack_depot_save+0x7c/0x460 lib/stackdepot.c:444 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x60/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] kmem_cache_free+0xf7/0x290 mm/slub.c:3709 anon_vma_chain_free mm/rmap.c:146 [inline] unlink_anon_vmas+0x2c8/0x660 mm/rmap.c:420 free_pgtables+0x24e/0x3d0 mm/memory.c:430 exit_mmap+0x33b/0x8e0 mm/mmap.c:3260 __mmput+0x118/0x3c0 kernel/fork.c:1200 exec_mmap+0x49b/0x550 fs/exec.c:1040 begin_new_exec+0xaa4/0x1ee0 fs/exec.c:1299 load_elf_binary+0x99f/0x26d0 fs/binfmt_elf.c:1028 search_binary_handler fs/exec.c:1764 [inline] exec_binprm fs/exec.c:1805 [inline] bprm_execve+0xb10/0x18a0 fs/exec.c:1874 do_execveat_common+0x51b/0x6c0 fs/exec.c:1979 do_execve fs/exec.c:2053 [inline] __do_sys_execve fs/exec.c:2129 [inline] __se_sys_execve fs/exec.c:2124 [inline] __x64_sys_execve+0x8e/0xa0 fs/exec.c:2124 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_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+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 __f_unlock_pos+0x0/0x20 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1bd/0x240 fs/read_write.c:640 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 *** 4 locks held by syz.5.1922/14653: #0: ffff88807851ed68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #2: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #2: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xf9/0x420 kernel/trace/bpf_trace.c:2326 #3: ffffffff8cb1ef40 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328 stack backtrace: CPU: 1 PID: 14653 Comm: syz.5.1922 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+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:__f_unlock_pos+0x0/0x20 fs/file.c:1044 Code: e9 fd fd ff ff 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 2e ff ff ff 4c 89 ff e8 5d 4d ea ff e9 21 ff ff ff 0f 1f 84 00 00 00 00 00 <53> 48 89 fb e8 67 1e 9a ff 48 83 eb 80 48 89 df 5b e9 1a 09 3a 08 RSP: 0018:ffffc90003b97e58 EFLAGS: 00000293 RAX: ffffffff81dec233 RBX: ffff88807851ec83 RCX: ffff888028921dc0 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88807851ec80 RBP: ffffc90003b97f10 R08: dffffc0000000000 R09: fffffbfff1c3ed56 R10: fffffbfff1c3ed56 R11: 1ffffffff1c3ed55 R12: 0000000000000001 R13: 0000000000000002 R14: 1ffff92000772fd0 R15: ffff88807851ed90 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1bd/0x240 fs/read_write.c:640 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: 0033:0x7f97bcd8e1ff 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:00007f97bdb67030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000a RCX: 00007f97bcd8e1ff RDX: 0000000000000001 RSI: 00007f97bdb67090 RDI: 000000000000000a RBP: 00007f97bdb67090 R08: 0000000000000000 R09: 00007f97bdb66df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f97bcfe6218 R14: 00007f97bcfe6180 R15: 00007ffd81ce43b8 CPU: 1 PID: 14653 Comm: syz.5.1922 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+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:__f_unlock_pos+0x0/0x20 fs/file.c:1044 Code: e9 fd fd ff ff 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 2e ff ff ff 4c 89 ff e8 5d 4d ea ff e9 21 ff ff ff 0f 1f 84 00 00 00 00 00 <53> 48 89 fb e8 67 1e 9a ff 48 83 eb 80 48 89 df 5b e9 1a 09 3a 08 RSP: 0018:ffffc90003b97e58 EFLAGS: 00000293 RAX: ffffffff81dec233 RBX: ffff88807851ec83 RCX: ffff888028921dc0 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88807851ec80 RBP: ffffc90003b97f10 R08: dffffc0000000000 R09: fffffbfff1c3ed56 R10: fffffbfff1c3ed56 R11: 1ffffffff1c3ed55 R12: 0000000000000001 R13: 0000000000000002 R14: 1ffff92000772fd0 R15: ffff88807851ed90 fdput_pos include/linux/file.h:80 [inline] ksys_write+0x1bd/0x240 fs/read_write.c:640 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: 0033:0x7f97bcd8e1ff 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:00007f97bdb67030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000a RCX: 00007f97bcd8e1ff RDX: 0000000000000001 RSI: 00007f97bdb67090 RDI: 000000000000000a RBP: 00007f97bdb67090 R08: 0000000000000000 R09: 00007f97bdb66df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f97bcfe6218 R14: 00007f97bcfe6180 R15: 00007ffd81ce43b8 ---------------- Code disassembly (best guess): 0: e9 fd fd ff ff jmp 0xfffffe02 5: 44 89 f9 mov %r15d,%ecx 8: 80 e1 07 and $0x7,%cl b: fe c1 inc %cl d: 38 c1 cmp %al,%cl f: 0f 8c 2e ff ff ff jl 0xffffff43 15: 4c 89 ff mov %r15,%rdi 18: e8 5d 4d ea ff call 0xffea4d7a 1d: e9 21 ff ff ff jmp 0xffffff43 22: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 29: 00 * 2a: 53 push %rbx <-- trapping instruction 2b: 48 89 fb mov %rdi,%rbx 2e: e8 67 1e 9a ff call 0xff9a1e9a 33: 48 83 eb 80 sub $0xffffffffffffff80,%rbx 37: 48 89 df mov %rbx,%rdi 3a: 5b pop %rbx 3b: e9 1a 09 3a 08 jmp 0x83a095a