============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u4:18/19162 is trying to acquire lock: ffffc900048a10d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc900049550d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 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 7 locks held by kworker/u4:18/19162: #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc90003907d00 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90003907d00 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff888059ec0768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5777 [inline] #2: ffff888059ec0768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_wiphy_work+0x35/0x260 net/wireless/core.c:424 #3: ffffffff8cd30000 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #3: ffffffff8cd30000 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2188 [inline] #3: ffffffff8cd30000 (rcu_callback){....}-{0:0}, at: rcu_core+0xc51/0x1720 kernel/rcu/tree.c:2467 #4: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #4: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #4: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #4: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf4/0x400 kernel/trace/bpf_trace.c:2362 #5: ffffc900049550d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c8/0x5a0 kernel/bpf/ringbuf.c:423 #6: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #6: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #6: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #6: ffffffff8cd2fee0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xde/0x3c0 kernel/trace/bpf_trace.c:2361 stack backtrace: CPU: 1 PID: 19162 Comm: kworker/u4:18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound cfg80211_wiphy_work Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c8/0x5a0 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_fe0ed97373b08409+0x2d/0x4a bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122 trace_contention_end+0xe6/0x110 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7ec/0x9d0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [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+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1c8/0x5a0 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_fe0ed97373b08409+0x2d/0x4a bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run3+0x1e7/0x400 kernel/trace/bpf_trace.c:2362 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x1e0/0x280 mm/slub.c:3851 dst_destroy+0x233/0x340 net/core/dst.c:121 rcu_do_batch kernel/rcu/tree.c:2194 [inline] rcu_core+0xcc4/0x1720 kernel/rcu/tree.c:2467 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009 Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 9b 58 e4 f6 e8 06 de 14 f7 fb bf 01 00 00 00 db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24 RSP: 0018:ffffc90003907940 EFLAGS: 00000286 RAX: 4595dd8b046f1800 RBX: 0000000000000000 RCX: 4595dd8b046f1800 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001 RBP: ffffc900039079e0 R08: ffffffff90da856f R09: 1ffffffff21b50ad R10: dffffc0000000000 R11: fffffbfff21b50ae R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000720f28 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:kcov_remote_start+0x2b/0x7f0 kernel/kcov.c:933 Code: 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 18 65 4c 8b 35 26 20 7e 7e 48 b8 00 00 00 00 ff ff ff 00 48 85 c7 74 11 0f 0b <48> 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 f8 48 c1 e8 39 RSP: 0018:ffffc90003907aa8 EFLAGS: 00000206 RAX: 4595dd8b046f1800 RBX: 0000000000000246 RCX: 4595dd8b046f1800 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00 RBP: ffff8880679b1780 R08: ffffffff90da856f R09: 1ffffffff21b50ad R10: dffffc0000000000 R11: fffffbfff21b50ae R12: 0000000000000000 R13: ffffffff8185980f R14: ffff88807d890000 R15: 0000000000000000 kcov_remote_start_common include/linux/kcov.h:50 [inline] ieee80211_iface_work+0x1f8/0xc70 net/mac80211/iface.c:1692 cfg80211_wiphy_work+0x225/0x260 net/wireless/core.c:437 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 ---------------- Code disassembly (best guess): 0: 44 24 20 rex.R and $0x20,%al 3: f6 44 24 21 02 testb $0x2,0x21(%rsp) 8: 74 0b je 0x15 a: 0f 0b ud2 c: 48 f7 03 08 00 00 00 testq $0x8,(%rbx) 13: 74 63 je 0x78 15: bf 01 00 00 00 mov $0x1,%edi 1a: e8 9b 58 e4 f6 call 0xf6e458ba 1f: e8 06 de 14 f7 call 0xf714de2a 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 db b5 ff ff call 0xffffb60a <-- trapping instruction 2f: 48 c7 44 24 40 00 00 movq $0x0,0x40(%rsp) 36: 00 00 38: 9c pushf 39: 8f 44 24 40 pop 0x40(%rsp) 3d: 8b .byte 0x8b 3e: 44 rex.R 3f: 24 .byte 0x24