FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 ====================================================== WARNING: possible circular locking dependency detected 6.16.0-rc2-syzkaller-00278-g3f75bfff44be #0 Not tainted ------------------------------------------------------ syz.3.685/8605 is trying to acquire lock: ffffffff8e4d1e00 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x9f/0xd0 kernel/printk/printk.c:1924 but task is already holding lock: ffff8880b843a2d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:614 [inline] ffff8880b843a2d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:599 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:606 raw_spin_rq_lock kernel/sched/sched.h:1532 [inline] task_rq_lock+0xcf/0x490 kernel/sched/core.c:708 cgroup_move_task+0x81/0x2a0 kernel/sched/psi.c:1161 css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:918 cgroup_post_fork+0x201/0x9e0 kernel/cgroup/cgroup.c:6754 copy_process+0x5cfc/0x76a0 kernel/fork.c:2413 kernel_clone+0xfc/0x960 kernel/fork.c:2599 user_mode_thread+0xc7/0x110 kernel/fork.c:2677 rest_init+0x23/0x2b0 init/main.c:710 start_kernel+0x3ee/0x4d0 init/main.c:1102 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 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+0xb2/0x1680 kernel/sched/core.c:4226 __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:89 __wake_up_common_lock kernel/sched/wait.c:106 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1838 serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1946 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1966 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x28e/0xab0 kernel/irq/chip.c:789 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:266 [inline] __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:292 common_interrupt+0x61/0xe0 arch/x86/kernel/irq.c:285 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 -> #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:105 [inline] __wake_up+0x1c/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1838 serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1946 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1966 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x28e/0xab0 kernel/irq/chip.c:789 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:266 [inline] __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:292 common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:285 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline] uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline] uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline] uart_write+0x2a4/0xb30 drivers/tty/serial/serial_core.c:637 process_output_block drivers/tty/n_tty.c:561 [inline] n_tty_write+0x40f/0x1160 drivers/tty/n_tty.c:2377 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.constprop.0+0x504/0x9b0 drivers/tty/tty_io.c:1081 tty_write drivers/tty/tty_io.c:1102 [inline] redirected_tty_write drivers/tty/tty_io.c:1125 [inline] redirected_tty_write+0xd4/0x150 drivers/tty/tty_io.c:1105 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6c4/0x1150 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #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:3415 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x801/0xc60 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3325 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450 _printk+0xc7/0x100 kernel/printk/printk.c:2475 register_console+0xc2d/0x11b0 kernel/printk/printk.c:4125 univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:513 console_init+0x14f/0x680 kernel/printk/printk.c:4323 start_kernel+0x29f/0x4d0 init/main.c:1036 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148 -> #0 (console_owner){-.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 console_lock_spinning_enable+0xb0/0xd0 kernel/printk/printk.c:1924 console_emit_next_record kernel/printk/printk.c:3132 [inline] console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3325 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450 _printk+0xc7/0x100 kernel/printk/printk.c:2475 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:193 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:221 bpf_prog_bc7c5c6b9645592f+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] bpf_trace_run4+0x249/0x5a0 kernel/trace/bpf_trace.c:2301 __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220 __traceiter_sched_switch+0x6f/0xc0 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+0x1bee/0x5de0 kernel/sched/core.c:6782 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:102 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 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 *** 4 locks held by syz.3.685/8605: #0: ffff8880b843a2d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:614 [inline] #0: ffff8880b843a2d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:599 #1: ffffffff8e5c4880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8e5c4880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8e5c4880 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline] #1: ffffffff8e5c4880 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x1cf/0x5a0 kernel/trace/bpf_trace.c:2301 #2: ffffffff8e5b2240 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2475 #3: ffffffff8e5b22b0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] #3: ffffffff8e5b22b0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:346 [inline] #3: ffffffff8e5b22b0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline] #3: ffffffff8e5b22b0 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3203 stack backtrace: CPU: 0 UID: 0 PID: 8605 Comm: syz.3.685 Not tainted 6.16.0-rc2-syzkaller-00278-g3f75bfff44be #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:2046 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 console_lock_spinning_enable+0xb0/0xd0 kernel/printk/printk.c:1924 console_emit_next_record kernel/printk/printk.c:3132 [inline] console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3325 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450 _printk+0xc7/0x100 kernel/printk/printk.c:2475 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:193 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:221 bpf_prog_bc7c5c6b9645592f+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] bpf_trace_run4+0x249/0x5a0 kernel/trace/bpf_trace.c:2301 __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220 __traceiter_sched_switch+0x6f/0xc0 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+0x1bee/0x5de0 kernel/sched/core.c:6782 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:102 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6e20d8d3df 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:00007f6e21bdd030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 0000000000000009 RCX: 00007f6e20d8d3df RDX: 0000000000000001 RSI: 00007f6e21bdd090 RDI: 0000000000000009 RBP: 00007f6e21bdd090 R08: 0000000000000000 R09: 00007f6e21bdcdf7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 0000000000000000 R14: 00007f6e20fb6160 R15: 00007ffe0608f888 CPU: 0 UID: 0 PID: 8605 Comm: syz.3.685 Not tainted 6.16.0-rc2-syzkaller-00278-g3f75bfff44be #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:193 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:221 bpf_prog_bc7c5c6b9645592f+0x3e/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] bpf_trace_run4+0x249/0x5a0 kernel/trace/bpf_trace.c:2301 __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220 __traceiter_sched_switch+0x6f/0xc0 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+0x1bee/0x5de0 kernel/sched/core.c:6782 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:102 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6e20d8d3df 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:00007f6e21bdd030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 0000000000000009 RCX: 00007f6e20d8d3df RDX: 0000000000000001 RSI: 00007f6e21bdd090 RDI: 0000000000000009 RBP: 00007f6e21bdd090 R08: 0000000000000000 R09: 00007f6e21bdcdf7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 0000000000000000 R14: 00007f6e20fb6160 R15: 00007ffe0608f888