============================================ WARNING: possible recursive locking detected 6.14.0-syzkaller-10514-g7f2ff7b62617 #0 Not tainted -------------------------------------------- kworker/3:0/34 is trying to acquire lock: ffffc90003f110d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc90006d510d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 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 9 locks held by kworker/3:0/34: #0: ffff88802a190148 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc900005cfd18 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffff888078f80538 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x42/0xca0 net/ipv6/mcast.c:2701 #3: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: mld_newpack.isra.0+0x357/0xa20 net/ipv6/mcast.c:1796 #4: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #4: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #4: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: ipv6_get_lladdr+0x3d/0x4f0 net/ipv6/addrconf.c:1930 #5: ffffffff8e3be7e0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #5: ffffffff8e3be7e0 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2562 [inline] #5: ffffffff8e3be7e0 (rcu_callback){....}-{0:0}, at: rcu_core+0x73d/0x14e0 kernel/rcu/tree.c:2824 #6: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #6: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #6: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2357 [inline] #6: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1b6/0x590 kernel/trace/bpf_trace.c:2399 #7: ffffc90006d510d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x36e/0x4b0 kernel/bpf/ringbuf.c:423 #8: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #8: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #8: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2357 [inline] #8: ffffffff8e3be900 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1b6/0x590 kernel/trace/bpf_trace.c:2399 stack backtrace: CPU: 3 UID: 0 PID: 34 Comm: kworker/3:0 Not tainted 6.14.0-syzkaller-10514-g7f2ff7b62617 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: mld mld_ifc_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_deadlock_bug+0x1e9/0x240 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain kernel/locking/lockdep.c:3896 [inline] __lock_acquire+0xff7/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 __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:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x57/0x90 kernel/bpf/ringbuf.c:466 bpf_prog_fe0ed97373b08409+0x2e/0x4b 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:2358 [inline] bpf_trace_run2+0x230/0x590 kernel/trace/bpf_trace.c:2399 __bpf_trace_contention_begin+0xc9/0x110 include/trace/events/lock.h:95 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline] class_preempt_notrace_destructor include/linux/preempt.h:482 [inline] __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin.constprop.0+0xde/0x160 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x109/0xcf0 kernel/locking/qspinlock.c:402 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:572 [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+0x20e/0x2b0 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:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x57/0x90 kernel/bpf/ringbuf.c:466 bpf_prog_f42551b0fba4abb2+0x2e/0x48 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:2358 [inline] bpf_trace_run2+0x230/0x590 kernel/trace/bpf_trace.c:2399 __do_trace_kfree include/trace/events/kmem.h:94 [inline] trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x236/0x4d0 mm/slub.c:4819 slab_free_after_rcu_debug+0x69/0x350 mm/slub.c:4670 rcu_do_batch kernel/rcu/tree.c:2568 [inline] rcu_core+0x799/0x14e0 kernel/rcu/tree.c:2824 handle_softirqs+0x216/0x8e0 kernel/softirq.c:561 do_softirq kernel/softirq.c:462 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:449 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:389 ipv6_get_lladdr+0x299/0x4f0 net/ipv6/addrconf.c:1935 mld_newpack.isra.0+0x41d/0xa20 net/ipv6/mcast.c:1802 add_grhead+0x299/0x340 net/ipv6/mcast.c:1899 add_grec+0x112a/0x1680 net/ipv6/mcast.c:2037 mld_send_cr net/ipv6/mcast.c:2163 [inline] mld_ifc_work+0x41f/0xca0 net/ipv6/mcast.c:2702 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245