============================================ WARNING: possible recursive locking detected 6.12.0-rc4-syzkaller-g9a28559932d2 #0 Not tainted -------------------------------------------- syz.4.207/6538 is trying to acquire lock: ffffc900047220d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 but task is already holding lock: ffffc900046610d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 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 3 locks held by syz.4.207/6538: #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: bpf_test_timer_enter+0x19/0x140 net/bpf/test_run.c:40 #1: ffffc900046610d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 #2: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbc/0x8a0 stack backtrace: CPU: 0 UID: 0 PID: 6538 Comm: syz.4.207 Not tainted 6.12.0-rc4-syzkaller-g9a28559932d2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:553 [inline] bpf_ringbuf_output+0x67/0x1e0 kernel/bpf/ringbuf.c:543 bpf_prog_4aaef4562453526c+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1290 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] bpf_prog_run_array include/linux/bpf.h:2165 [inline] trace_call_bpf+0x369/0x8a0 kernel/trace/bpf_trace.c:146 perf_trace_run_bpf_submit+0x82/0x180 kernel/events/core.c:10416 perf_trace_lock+0x388/0x490 include/trace/events/lock.h:50 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x9cc/0xa30 kernel/locking/lockdep.c:5836 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194 __bpf_ringbuf_reserve+0x48a/0x600 kernel/bpf/ringbuf.c:465 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:478 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:470 bpf_prog_87238a5d08231a3d+0x2e/0x4d __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run_xdp include/net/xdp.h:514 [inline] bpf_test_run+0x4b1/0xa90 net/bpf/test_run.c:431 bpf_prog_test_run_xdp+0x7da/0x11e0 net/bpf/test_run.c:1319 bpf_prog_test_run+0x2e4/0x360 kernel/bpf/syscall.c:4367 __sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5772 __do_sys_bpf kernel/bpf/syscall.c:5861 [inline] __se_sys_bpf kernel/bpf/syscall.c:5859 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5859 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f896357e719 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:00007f896445b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8963735f80 RCX: 00007f896357e719 RDX: 0000000000000050 RSI: 0000000020000240 RDI: 000000000000000a RBP: 00007f89635f139e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f8963735f80 R15: 00007ffd294ed928