====================================================== WARNING: possible circular locking dependency detected 5.15.179-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.23593/20868 is trying to acquire lock: ffff88807a2dbdb8 (&trie->lock){....}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467 but task is already holding lock: ffff8880b8f3a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&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 -> #4 (&p->pi_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 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 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 unwind_next_frame+0x680/0x1fa0 arch/x86/kernel/unwind_orc.c:475 arch_stack_walk+0x10d/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kmem_cache_free+0x91/0x1f0 mm/slub.c:3515 remove_vma mm/mmap.c:187 [inline] exit_mmap+0x4ff/0x620 mm/mmap.c:3215 __mmput+0x112/0x3b0 kernel/fork.c:1127 exit_mm+0x688/0x7f0 kernel/exit.c:550 do_exit+0x626/0x2480 kernel/exit.c:861 do_group_exit+0x144/0x310 kernel/exit.c:996 __do_sys_exit_group kernel/exit.c:1007 [inline] __se_sys_exit_group kernel/exit.c:1005 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005 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 -> #3 (&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 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] uart_write+0x6af/0x930 drivers/tty/serial/serial_core.c:592 process_output_block drivers/tty/n_tty.c:592 [inline] n_tty_write+0xd7e/0x1280 drivers/tty/n_tty.c:2339 do_tty_write drivers/tty/tty_io.c:1038 [inline] file_tty_write+0x561/0x920 drivers/tty/tty_io.c:1110 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 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 (&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 -> #1 (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 -> #0 (&trie->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 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467 bpf_prog_2f7803a8c7e47c22+0x64/0x860 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:621 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run2+0x29e/0x340 kernel/trace/bpf_trace.c:1915 trace_tlb_flush+0xed/0x110 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x748/0xa30 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5015 [inline] __schedule+0x1167/0x45b0 kernel/sched/core.c:6375 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 other info that might help us debug this: Chain exists of: &trie->lock --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock(&trie->lock); *** DEADLOCK *** 2 locks held by syz.3.23593/20868: #0: ffff8880b8f3a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 #1: ffffffff8cb1f4e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 1 PID: 20868 Comm: syz.3.23593 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 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467 bpf_prog_2f7803a8c7e47c22+0x64/0x860 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:621 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run2+0x29e/0x340 kernel/trace/bpf_trace.c:1915 trace_tlb_flush+0xed/0x110 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x748/0xa30 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5015 [inline] __schedule+0x1167/0x45b0 kernel/sched/core.c:6375 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 RIP: 0033:0x7fb3e5f49169 Code: Unable to access opcode bytes at RIP 0x7fb3e5f4913f. RSP: 002b:00007fb3e3db20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fb3e6161fa8 RCX: 00007fb3e5f49169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb3e6161fa8 RBP: 00007fb3e6161fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb3e6161fac R13: 0000000000000000 R14: 00007ffd5d2c1120 R15: 00007ffd5d2c1208