============================================
WARNING: possible recursive locking detected
6.1.131-syzkaller #0 Not tainted
--------------------------------------------
syz.8.2065/10902 is trying to acquire lock:
ffffc90004ecd0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
but task is already holding lock:
ffffc900051220d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
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
5 locks held by syz.8.2065/10902:
#0: ffff888079e117d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff888079e117d8 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x28c/0x980 mm/mmap.c:3246
#1: ffffffff8d32e780 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#1: ffffffff8d32e780 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2291 [inline]
#1: ffffffff8d32e780 (rcu_callback){....}-{0:0}, at: rcu_core+0xa6b/0x1820 kernel/rcu/tree.c:2557
#2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
#2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2324
#3: ffffc900051220d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
#4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
#4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2323
stack backtrace:
CPU: 0 PID: 10902 Comm: syz.8.2065 Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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
__bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
____bpf_ringbuf_output kernel/bpf/ringbuf.c:539 [inline]
bpf_ringbuf_output+0x63/0x1e0 kernel/bpf/ringbuf.c:529
bpf_prog_044b88d9c832e6f0+0x45/0x49
bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline]
__bpf_prog_run include/linux/filter.h:596 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
bpf_trace_run2+0x361/0x410 kernel/trace/bpf_trace.c:2323
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
__bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:464 [inline]
bpf_ringbuf_reserve+0x58/0x70 kernel/bpf/ringbuf.c:456
bpf_prog_fe0ed97373b08409+0x25/0x42
bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline]
__bpf_prog_run include/linux/filter.h:596 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
bpf_trace_run3+0x3a1/0x440 kernel/trace/bpf_trace.c:2324
__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
taskstats_tgid_free include/linux/taskstats_kern.h:22 [inline]
free_signal_struct+0x73/0x210 kernel/fork.c:821
put_signal_struct kernel/fork.c:835 [inline]
__put_task_struct+0x1c6/0x280 kernel/fork.c:850
rcu_do_batch kernel/rcu/tree.c:2297 [inline]
rcu_core+0xade/0x1820 kernel/rcu/tree.c:2557
handle_softirqs+0x2ee/0xa40 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0x157/0x240 kernel/softirq.c:661
irq_exit_rcu+0x5/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 52 0e 26 f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 57 9c a2 f6 65 8b 05 78 72 46 75 85 c0 74 3f 48 c7 04 24 0e 36
RSP: 0018:ffffc90004a3f860 EFLAGS: 00000206
RAX: 8faae17ae05aca00 RBX: 1ffff92000947f10 RCX: ffffffff816b249a
RDX: dffffc0000000000 RSI: ffffffff8b0c1d40 RDI: 0000000000000001
RBP: ffffc90004a3f8f0 R08: dffffc0000000000 R09: fffffbfff2257253
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff92000947f0c R14: ffffc90004a3f880 R15: 0000000000000246
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1611 [inline]
release_pages+0x214/0x27a0 mm/swap.c:986
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
exit_mmap+0x3b3/0x980 mm/mmap.c:3250
__mmput+0x115/0x3c0 kernel/fork.c:1200
exit_mm+0x226/0x300 kernel/exit.c:565
do_exit+0x9f1/0x26a0 kernel/exit.c:858
__do_sys_exit kernel/exit.c:988 [inline]
__se_sys_exit kernel/exit.c:986 [inline]
__x64_sys_exit+0x3c/0x40 kernel/exit.c:986
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff768b8d169
Code: Unable to access opcode bytes at 0x7ff768b8d13f.
RSP: 002b:00007ff769977fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007ff768da5fa0 RCX: 00007ff768b8d169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ff768c0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff768da5fa0 R15: 00007ffddce66a48
----------------
Code disassembly (best guess):
0: 9c pushf
1: 8f 44 24 20 pop 0x20(%rsp)
5: 42 80 3c 23 00 cmpb $0x0,(%rbx,%r12,1)
a: 74 08 je 0x14
c: 4c 89 f7 mov %r14,%rdi
f: e8 52 0e 26 f7 call 0xf7260e66
14: f6 44 24 21 02 testb $0x2,0x21(%rsp)
19: 75 4e jne 0x69
1b: 41 f7 c7 00 02 00 00 test $0x200,%r15d
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 57 9c a2 f6 call 0xf6a29c86 <-- trapping instruction
2f: 65 8b 05 78 72 46 75 mov %gs:0x75467278(%rip),%eax # 0x754672ae
36: 85 c0 test %eax,%eax
38: 74 3f je 0x79
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss