============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.6.5433/25981 is trying to acquire lock: ffffc90004b330d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:425 but task is already holding lock: ffffc90004a310d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:425 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 syz.6.5433/25981: #0: ffff8880b8f3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 #1: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #1: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #1: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #1: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xfd/0x420 kernel/trace/bpf_trace.c:2363 #2: ffffc90004a310d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:425 #3: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #3: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #3: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xc3/0x690 kernel/trace/bpf_trace.c:142 stack backtrace: CPU: 1 PID: 25981 Comm: syz.6.5433 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:425 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:476 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:468 bpf_prog_df2ea1bb7efca089+0x35/0x4f bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] bpf_prog_run_array include/linux/bpf.h:1994 [inline] trace_call_bpf+0x321/0x690 kernel/trace/bpf_trace.c:143 perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10263 perf_trace_contention_begin+0x254/0x2f0 include/trace/events/lock.h:95 trace_contention_begin+0xe9/0x110 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0xe0/0x9d0 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:425 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:476 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:468 bpf_prog_a15678292f806a34+0x30/0x4a bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2197/0x44d0 kernel/sched/core.c:6696 schedule+0xbd/0x170 kernel/sched/core.c:6773 do_nanosleep+0x1ad/0x5f0 kernel/time/hrtimer.c:2091 hrtimer_nanosleep+0x15f/0x350 kernel/time/hrtimer.c:2139 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1397 [inline] __se_sys_clock_nanosleep+0x2ea/0x370 kernel/time/posix-timers.c:1374 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3a937c2005 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8 RSP: 002b:00007fffaa948290 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 00007f3a939e5fa0 RCX: 00007f3a937c2005 RDX: 00007fffaa9482d0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f3a939e7da0 R08: 0000000000000000 R09: 0000000000745d1e R10: 0000000000000000 R11: 0000000000000293 R12: 000000000012abc3 R13: 00007f3a939e6090 R14: ffffffffffffffff R15: 00007fffaa948410