====================================================== WARNING: possible circular locking dependency detected 5.15.179-syzkaller #0 Not tainted ------------------------------------------------------ syz.4.288/5322 is trying to acquire lock: ffff888023f1c5a8 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xae/0x12c0 kernel/sched/core.c:4029 but task is already holding lock: ffff88807eafa528 (&tty->write_wait){-...}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline] ffff88807eafa528 (&tty->write_wait){-...}-{2:2}, at: __wake_up+0xf5/0x1c0 kernel/sched/wait.c:157 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&tty->write_wait){-...}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:137 [inline] __wake_up+0xf5/0x1c0 kernel/sched/wait.c:157 tty_port_default_wakeup+0xa8/0x100 drivers/tty/tty_port.c:51 serial8250_tx_chars+0x60d/0x800 drivers/tty/serial/8250/8250_port.c:1828 serial8250_handle_irq+0x505/0x600 drivers/tty/serial/8250/8250_port.c:1924 serial8250_default_handle_irq+0xc8/0x1e0 drivers/tty/serial/8250/8250_port.c:1941 serial8250_interrupt+0xa1/0x1e0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x292/0xa70 kernel/irq/handle.c:156 handle_irq_event_percpu kernel/irq/handle.c:196 [inline] handle_irq_event+0xff/0x2b0 kernel/irq/handle.c:213 handle_edge_irq+0x245/0xbf0 kernel/irq/chip.c:819 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0xd7/0x1f0 arch/x86/kernel/irq.c:250 common_interrupt+0xae/0xd0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline] acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562 acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:697 cpuidle_enter_state+0x521/0xef0 drivers/cpuidle/cpuidle.c:237 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351 call_cpuidle kernel/sched/idle.c:158 [inline] cpuidle_idle_call kernel/sched/idle.c:239 [inline] do_idle+0x3e4/0x670 kernel/sched/idle.c:306 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb -> #4 (&port_lock_key){-...}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 serial8250_console_write+0x19d/0x1180 drivers/tty/serial/8250/8250_port.c:3363 call_console_drivers kernel/printk/printk.c:-1 [inline] console_unlock+0xced/0x12b0 kernel/printk/printk.c:2744 vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274 _printk+0xd1/0x120 kernel/printk/printk.c:2299 register_console+0x65a/0x940 kernel/printk/printk.c:3107 univ8250_console_init+0x41/0x50 drivers/tty/serial/8250/8250_core.c:690 console_init+0x18c/0x660 kernel/printk/printk.c:3207 start_kernel+0x301/0x540 init/main.c:1076 secondary_startup_64_no_verify+0xb1/0xbb -> #3 (console_owner){....}-{0:0}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 console_lock_spinning_enable+0x51/0x60 kernel/printk/printk.c:1805 console_unlock+0xa47/0x12b0 kernel/printk/printk.c:2741 vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274 _printk+0xd1/0x120 kernel/printk/printk.c:2299 debug_objects_oom+0xb4/0x370 lib/debugobjects.c:473 debug_object_activate+0x42d/0x4e0 lib/debugobjects.c:699 debug_rcu_head_queue kernel/rcu/rcu.h:176 [inline] kvfree_call_rcu+0xb6/0x8a0 kernel/rcu/tree.c:3587 trie_update_elem+0x8ad/0xca0 kernel/bpf/lpm_trie.c:396 bpf_map_update_value+0x5d7/0x6c0 kernel/bpf/syscall.c:221 generic_map_update_batch+0x54d/0x8b0 kernel/bpf/syscall.c:1421 bpf_map_do_batch+0x4d0/0x620 kernel/bpf/syscall.c:-1 __sys_bpf+0x55c/0x670 kernel/bpf/syscall.c:-1 __do_sys_bpf kernel/bpf/syscall.c:4752 [inline] __se_sys_bpf kernel/bpf/syscall.c:4750 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4750 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (&trie->lock){....}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467 0xffffffffa002a5e1 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 __traceiter_sched_switch+0x7d/0xb0 include/trace/events/sched.h:220 trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x1e8d/0x45b0 kernel/sched/core.c:6372 schedule+0x11b/0x1f0 kernel/sched/core.c:6458 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x25b/0x480 kernel/futex/core.c:2863 futex_wait+0x2f8/0x740 kernel/futex/core.c:2964 do_futex+0x1414/0x1810 kernel/futex/core.c:3982 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x407/0x490 kernel/futex/core.c:4040 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 raw_spin_rq_lock kernel/sched/sched.h:1326 [inline] rq_lock kernel/sched/sched.h:1621 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11499 sched_cgroup_fork+0x2d3/0x330 kernel/sched/core.c:4465 copy_process+0x224a/0x3ef0 kernel/fork.c:2319 kernel_clone+0x210/0x960 kernel/fork.c:2603 kernel_thread+0x12e/0x1a0 kernel/fork.c:2655 rest_init+0x21/0x330 init/main.c:706 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb -> #0 (&p->pi_lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xae/0x12c0 kernel/sched/core.c:4029 __wake_up_common+0x2a0/0x4e0 kernel/sched/wait.c:108 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x112/0x1c0 kernel/sched/wait.c:157 pty_close+0x253/0x420 drivers/tty/pty.c:68 tty_release+0x3a7/0x1310 drivers/tty/tty_io.c:1773 __fput+0x3fe/0x8e0 fs/file_table.c:311 task_work_run+0x129/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &p->pi_lock --> &port_lock_key --> &tty->write_wait Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&tty->write_wait); lock(&port_lock_key); lock(&tty->write_wait); lock(&p->pi_lock); *** DEADLOCK *** 2 locks held by syz.4.288/5322: #0: ffff8880624a81c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_release+0xac/0x1310 drivers/tty/tty_io.c:1755 #1: ffff88807eafa528 (&tty->write_wait){-...}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline] #1: ffff88807eafa528 (&tty->write_wait){-...}-{2:2}, at: __wake_up+0xf5/0x1c0 kernel/sched/wait.c:157 stack backtrace: CPU: 1 PID: 5322 Comm: syz.4.288 Not tainted 5.15.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xae/0x12c0 kernel/sched/core.c:4029 __wake_up_common+0x2a0/0x4e0 kernel/sched/wait.c:108 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x112/0x1c0 kernel/sched/wait.c:157 pty_close+0x253/0x420 drivers/tty/pty.c:68 tty_release+0x3a7/0x1310 drivers/tty/tty_io.c:1773 __fput+0x3fe/0x8e0 fs/file_table.c:311 task_work_run+0x129/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fb8c2d44169 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:00007ffec233cb78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fb8c2f5eba0 RCX: 00007fb8c2d44169 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fb8c2f5eba0 R08: 00000000000000e8 R09: 0000000dc233ce6f R10: 00007fb8c2f5eac0 R11: 0000000000000246 R12: 000000000002d85c R13: 00007ffec233cc70 R14: ffffffffffffffff R15: 00007ffec233cc90