============================================ WARNING: possible recursive locking detected 6.12.0-rc6-syzkaller-00169-g906bd684e4b1 #0 Not tainted -------------------------------------------- udevd/5943 is trying to acquire lock: ffffc900040c60d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:427 but task is already holding lock: ffffc900043560d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 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 udevd/5943: #0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2315 [inline] #0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x1d1/0x5a0 kernel/trace/bpf_trace.c:2358 #1: ffffc900043560d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:427 #2: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2315 [inline] #2: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2357 stack backtrace: CPU: 3 UID: 0 PID: 5943 Comm: udevd Not tainted 6.12.0-rc6-syzkaller-00169-g906bd684e4b1 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_deadlock_bug+0x2e3/0x410 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain kernel/locking/lockdep.c:3891 [inline] __lock_acquire+0x2185/0x3ce0 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:427 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:478 [inline] bpf_ringbuf_reserve+0x57/0x90 kernel/bpf/ringbuf.c:470 bpf_prog_0e153dac479590bf+0x35/0x70 bpf_dispatcher_nop_func include/linux/bpf.h:1265 [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:2316 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2357 __bpf_trace_contention_begin+0xca/0x110 include/trace/events/lock.h:95 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline] trace_contention_begin.constprop.0+0xed/0x170 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x10b/0xc90 kernel/locking/qspinlock.c:402 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [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+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:427 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:478 [inline] bpf_ringbuf_reserve+0x57/0x90 kernel/bpf/ringbuf.c:470 bpf_prog_fe0ed97373b08409+0x2e/0x4b bpf_dispatcher_nop_func include/linux/bpf.h:1265 [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:2316 [inline] bpf_trace_run3+0x240/0x5a0 kernel/trace/bpf_trace.c:2358 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x200/0x4b0 mm/slub.c:4680 putname+0x12e/0x170 fs/namei.c:280 vfs_fstatat+0xa9/0x160 fs/stat.c:342 __do_sys_newfstatat+0xa2/0x130 fs/stat.c:505 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3ef1d165f4 Code: 64 c7 00 09 00 00 00 83 c8 ff c3 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 00 00 00 00 41 89 ca b8 06 01 00 00 0f 05 <45> 31 c0 3d 00 f0 ff ff 76 10 48 8b 15 03 a8 0d 00 f7 d8 41 83 c8 RSP: 002b:00007fff244103a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055db8ade81f0 RCX: 00007f3ef1d165f4 RDX: 00007fff244103b8 RSI: 00007fff24410848 RDI: 00000000ffffff9c RBP: 00007fff24410448 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff24410848 R13: 00007fff244103b8 R14: 000055db8adaf2c0 R15: 000055db78159a04