============================================ WARNING: possible recursive locking detected 6.14.0-rc1-syzkaller-g4eb93fea5919 #0 Not tainted -------------------------------------------- udevd/5843 is trying to acquire lock: ffff88805fa991e0 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140 but task is already holding lock: ffff8880320091e0 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x1b2/0x660 kernel/bpf/queue_stack_maps.c:210 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qs->lock); lock(&qs->lock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by udevd/5843: #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2370 [inline] #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run3+0x24c/0x5a0 kernel/trace/bpf_trace.c:2413 #1: ffff8880320091e0 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x1b2/0x660 kernel/bpf/queue_stack_maps.c:210 #2: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2370 [inline] #2: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2412 stack backtrace: CPU: 0 UID: 0 PID: 5843 Comm: udevd Not tainted 6.14.0-rc1-syzkaller-g4eb93fea5919 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 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:3039 check_deadlock kernel/locking/lockdep.c:3091 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3893 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140 bpf_prog_00798911c748094f+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_trace_run kernel/trace/bpf_trace.c:2371 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2412 __bpf_trace_contention_end+0x170/0x230 include/trace/events/lock.h:122 __do_trace_contention_end include/trace/events/lock.h:122 [inline] trace_contention_end+0x118/0x140 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:577 [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 queue_stack_map_push_elem+0x1b2/0x660 kernel/bpf/queue_stack_maps.c:210 bpf_prog_216c997a1f42e404+0x40/0x44 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_trace_run kernel/trace/bpf_trace.c:2371 [inline] bpf_trace_run3+0x33a/0x5a0 kernel/trace/bpf_trace.c:2413 __do_trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x367/0x410 mm/slub.c:4710 do_readlinkat+0x2be/0x3a0 fs/stat.c:582 __do_sys_readlink fs/stat.c:599 [inline] __se_sys_readlink fs/stat.c:596 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:596 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: 0033:0x7fcaf5117d47 Code: 73 01 c3 48 8b 0d e1 90 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b1 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffdf0bd5858 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007ffdf0bd5868 RCX: 00007fcaf5117d47 RDX: 0000000000000400 RSI: 00007ffdf0bd5868 RDI: 00007ffdf0bd5d48 RBP: 0000000000000400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdf0bd5d48 R13: 00007ffdf0bd5cb8 R14: 0000555bf07a0910 R15: 0000555bd415ca04