============================================ WARNING: possible recursive locking detected 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0 Not tainted -------------------------------------------- syz.5.790/8511 is trying to acquire lock: ffffc9000476d0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc900048890d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 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 3 locks held by syz.5.790/8511: #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2370 [inline] #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run3+0x24c/0x5a0 kernel/trace/bpf_trace.c:2413 #1: ffffc900048890d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:423 #2: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2370 [inline] #2: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2412 stack backtrace: CPU: 1 UID: 0 PID: 8511 Comm: syz.5.790 Not tainted 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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 __bpf_ringbuf_reserve+0x1ea/0x600 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+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:2371 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2412 __bpf_trace_contention_begin+0x170/0x230 include/trace/events/lock.h:95 __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin+0x11b/0x140 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x114/0xdb0 kernel/locking/qspinlock.c:402 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 __bpf_ringbuf_reserve+0x1ea/0x600 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+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: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 file_free fs/file_table.c:68 [inline] __fput+0x63f/0x9f0 fs/file_table.c:477 task_work_run+0x24f/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2a/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x168c/0x1720 kernel/signal.c:3036 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f079298d169 Code: Unable to access opcode bytes at 0x7f079298d13f. RSP: 002b:00007f07938970e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f0792ba5fa8 RCX: 00007f079298d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0792ba5fa8 RBP: 00007f0792ba5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0792ba5fac R13: 0000000000000000 R14: 00007fff305ecac0 R15: 00007fff305ecba8