============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.7.6250/26394 is trying to acquire lock: ffff888026fcaa18 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 but task is already holding lock: ffff888026fcaa18 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x11a/0x440 kernel/bpf/queue_stack_maps.c:144 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 syz.7.6250/26394: #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf0/0x400 kernel/trace/bpf_trace.c:2325 #1: ffff888026fcaa18 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x11a/0x440 kernel/bpf/queue_stack_maps.c:144 #2: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #2: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 stack backtrace: CPU: 1 PID: 26394 Comm: syz.7.6250 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 bpf_prog_80daba7f9ca62790+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1012 [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:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_contention_begin+0x142/0x190 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0xdc/0x9c0 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [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+0x217/0x280 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb0/0xf0 kernel/locking/spinlock.c:162 __stack_map_get+0x11a/0x440 kernel/bpf/queue_stack_maps.c:144 bpf_prog_94b194d4ebfffdd5+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:1012 [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:2285 [inline] bpf_trace_run3+0x1e3/0x400 kernel/trace/bpf_trace.c:2325 __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+0x1ef/0x290 mm/slub.c:3708 put_pid+0xb0/0x120 kernel/pid.c:114 release_task+0x14fb/0x1600 kernel/exit.c:279 exit_notify kernel/exit.c:763 [inline] do_exit+0x17e1/0x2400 kernel/exit.c:892 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:288 RIP: 0033:0x7fbf5ddc3e89 Code: Unable to access opcode bytes at 0x7fbf5ddc3e5f. RSP: 002b:00007fbf5ec181c0 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3 RAX: 0000000000000000 RBX: 00007fbf5dd462a0 RCX: 00007fbf5ddc3e89 RDX: 00007fbf5dd462a0 RSI: 0000000000000058 RDI: 00007ffeae423fe0 RBP: 00007fbf5ec186c0 R08: 00007fbf5ec186c0 R09: 00007ffeae4240c7 R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8 R13: 000000000000006e R14: 00007ffeae423fe0 R15: 00007ffeae4240c8