syzbot

============================================
WARNING: possible recursive locking detected
6.11.0-syzkaller-10555-gbcd28cfd04eb #0 Not tainted
--------------------------------------------
syz-executor647/5299 is trying to acquire lock:
ffffc900097650d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427

but task is already holding lock:
ffffc9000aa450d8 (&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-executor647/5299:
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2317 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2359
 #1: ffffc9000aa450d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427
 #2: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbc/0x8a0

stack backtrace:
CPU: 1 UID: 0 PID: 5299 Comm: syz-executor647 Not tainted 6.11.0-syzkaller-10555-gbcd28cfd04eb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __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:3034
 check_deadlock kernel/locking/lockdep.c:3086 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3888
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 __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:1257 [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:2123 [inline]
 trace_call_bpf+0x369/0x8a0 kernel/trace/bpf_trace.c:146
 perf_trace_run_bpf_submit+0x82/0x180 kernel/events/core.c:10417
 perf_trace_lock_acquire+0x3c3/0x4f0 include/trace/events/lock.h:24
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x51b/0x550 kernel/locking/lockdep.c:5793
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2317 [inline]
 bpf_trace_run2+0x219/0x540 kernel/trace/bpf_trace.c:2359
 __traceiter_contention_end+0x7b/0xb0 include/trace/events/lock.h:122
 trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
 __pv_queued_spin_lock_slowpath+0xb7e/0xdb0 kernel/locking/qspinlock.c:557
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
 queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162
 __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427
 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:478 [inline]
 bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:470
 bpf_prog_f42551b0fba4abb2+0x2e/0x48
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359
 __traceiter_kfree+0x2b/0x50 include/trace/events/kmem.h:94
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0x35e/0x440 mm/slub.c:4715
 bpf_check+0x1b421/0x1e320 kernel/bpf/verifier.c:22428
 bpf_prog_load+0x1667/0x20f0 kernel/bpf/syscall.c:2846
 __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5634
 __do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739
 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: 0033:0x7f6682fc85a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffefabbb128 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6682fc85a9
RDX: 0000000000000080 RSI: 0000000020000200 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000000a0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>