============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- rcu_preempt/16 is trying to acquire lock: ffffc9000d3b30d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc9000d3310d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&rb->spinlock); lock(&rb->spinlock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by rcu_preempt/16: #0: ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636 #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4b0 kernel/trace/bpf_trace.c:2298 #2: ffffc9000d3310d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: trace_call_bpf+0xb7/0x850 kernel/trace/bpf_trace.c:-1 stack backtrace: CPU: 0 UID: 0 PID: 16 Comm: rcu_preempt Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_df2ea1bb7efca089+0x36/0x54 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] bpf_prog_run_array include/linux/bpf.h:2292 [inline] trace_call_bpf+0x326/0x850 kernel/trace/bpf_trace.c:146 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:10911 do_perf_trace_contention_end include/trace/events/lock.h:122 [inline] perf_trace_contention_end+0x253/0x2f0 include/trace/events/lock.h:122 __do_trace_contention_end include/trace/events/lock.h:122 [inline] trace_contention_end+0x111/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x9f9/0xb60 kernel/locking/qspinlock.c:374 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_6979e45824a16319+0x36/0x66 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [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:2257 [inline] bpf_trace_run2+0x281/0x4b0 kernel/trace/bpf_trace.c:2298 __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:38 __traceiter_tlb_flush+0x76/0xd0 include/trace/events/tlb.h:38 __do_trace_tlb_flush include/trace/events/tlb.h:38 [inline] trace_tlb_flush+0x115/0x140 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x53e/0x7a0 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5341 [inline] __schedule+0x110e/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245