============================================ WARNING: possible recursive locking detected 6.1.94-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:0/9 is trying to acquire lock: ffff888019310218 (&qs->lock){..-.}-{2:2}, at: __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 but task is already holding lock: ffff888019310218 (&qs->lock){..-.}-{2:2}, at: queue_stack_map_push_elem+0x1ac/0x650 kernel/bpf/queue_stack_maps.c:214 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 6 locks held by kworker/u4:0/9: #0: ffff88814b945938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900000e7d20 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8d12ad80 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8d12ad80 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2291 [inline] #2: ffffffff8d12ad80 (rcu_callback){....}-{0:0}, at: rcu_core+0xa6b/0x1810 kernel/rcu/tree.c:2556 #3: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #3: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2313 #4: ffff888019310218 (&qs->lock){..-.}-{2:2}, at: queue_stack_map_push_elem+0x1ac/0x650 kernel/bpf/queue_stack_maps.c:214 #5: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #5: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #5: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #5: ffffffff8d12acc0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2312 stack backtrace: CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted 6.1.94-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: bat_events batadv_nc_worker 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 __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 bpf_prog_94b194d4ebfffdd5+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 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 queue_stack_map_push_elem+0x1ac/0x650 kernel/bpf/queue_stack_maps.c:214 bpf_prog_216c997a1f42e404+0x37/0x3b 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_run3+0x231/0x440 kernel/trace/bpf_trace.c:2313 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:114 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x418/0x510 mm/slub.c:3682 rcu_do_batch kernel/rcu/tree.c:2296 [inline] rcu_core+0xad5/0x1810 kernel/rcu/tree.c:2556 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 do_softirq+0x162/0x240 kernel/softirq.c:472 __local_bh_enable_ip+0x1b1/0x1f0 kernel/softirq.c:396 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_nc_purge_paths+0x30e/0x3b0 net/batman-adv/network-coding.c:471 batadv_nc_worker+0x324/0x610 net/batman-adv/network-coding.c:720 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308