============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- udevd/5233 is trying to acquire lock: ffffc9000bf810d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc9000bfa50d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 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 udevd/5233: #0: ffff88802e4d40f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1232 #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline] #1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4b0 kernel/trace/bpf_trace.c:2298 #2: ffffc9000bfa50d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline] #3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4b0 kernel/trace/bpf_trace.c:2298 stack backtrace: CPU: 0 UID: 0 PID: 5233 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_7593138e1bd8a8e8+0x3f/0x8c bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline] bpf_trace_run2+0x281/0x4b0 kernel/trace/bpf_trace.c:2298 __bpf_trace_contention_end+0xdc/0x130 include/trace/events/lock.h:122 __traceiter_contention_end+0x7a/0xb0 include/trace/events/lock.h:122 __do_trace_contention_end include/trace/events/lock.h:122 [inline] trace_contention_end+0x111/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x9f9/0xb60 kernel/locking/qspinlock.c:374 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_7593138e1bd8a8e8+0x3f/0x8c bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline] bpf_trace_run2+0x281/0x4b0 kernel/trace/bpf_trace.c:2298 __bpf_trace_contention_end+0xdc/0x130 include/trace/events/lock.h:122 __traceiter_contention_end+0x7a/0xb0 include/trace/events/lock.h:122 __do_trace_contention_end include/trace/events/lock.h:122 [inline] trace_contention_end+0xf4/0x120 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:607 [inline] __mutex_lock+0x32b/0x1360 kernel/locking/mutex.c:760 fdget_pos+0x247/0x320 fs/file.c:1232 class_fd_pos_constructor include/linux/file.h:85 [inline] __do_sys_getdents64 fs/readdir.c:399 [inline] __se_sys_getdents64+0x8f/0x260 fs/readdir.c:396 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4d66af0d23 Code: 8b 05 d9 00 10 00 64 c7 00 16 00 00 00 31 c0 eb b0 66 0f 1f 44 00 00 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 a1 00 10 00 f7 d8 RSP: 002b:00007fff15eeb6f8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 000055da45413100 RCX: 00007f4d66af0d23 RDX: 0000000000008000 RSI: 000055da45413130 RDI: 000000000000000c RBP: 000055da45413104 R08: 00007f4d66bf1ac0 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000293 R12: 000055da45413130 R13: fffffffffffffe68 R14: 0000000000000016 R15: 00007fff15eeb9e0