============================================ WARNING: possible recursive locking detected 6.1.100-syzkaller #0 Not tainted -------------------------------------------- syz.4.318/4417 is trying to acquire lock: ffffc900033090d8 (&rb->spinlock){..-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 but task is already holding lock: ffffc900032e70d8 (&rb->spinlock){..-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 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.4.318/4417: #0: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #0: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2312 #1: ffffc900032e70d8 (&rb->spinlock){..-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 #2: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #2: ffffffff8d12ad40 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2312 stack backtrace: CPU: 0 PID: 4417 Comm: syz.4.318 Not tainted 6.1.100-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:539 [inline] bpf_ringbuf_output+0x63/0x1e0 kernel/bpf/ringbuf.c:529 bpf_prog_918f90024333f9ff+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312 trace_contention_end+0x14c/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x935/0xc50 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [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+0x269/0x370 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xdd/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:539 [inline] bpf_ringbuf_output+0x63/0x1e0 kernel/bpf/ringbuf.c:529 bpf_prog_a3e2825f60354855+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18 trace_sys_enter include/trace/events/syscalls.h:18 [inline] syscall_trace_enter kernel/entry/common.c:81 [inline] __syscall_enter_from_user_work kernel/entry/common.c:100 [inline] syscall_enter_from_user_mode+0x206/0x230 kernel/entry/common.c:118 do_syscall_64+0x1e/0xb0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8d8f9a7f05 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 c6 57 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 1f 58 ff ff 48 8b 04 24 48 83 c4 28 f7 d8 RSP: 002b:00007ffd1d1c13b0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 00007f8d8fb05f60 RCX: 00007f8d8f9a7f05 RDX: 00007ffd1d1c13f0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f8d8fb07a60 R08: 0000000000000000 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000016ca8 R13: 0000000000000032 R14: 00007f8d8fb07a60 R15: 00007ffd1d1c1500