============================================
WARNING: possible recursive locking detected
6.1.131-syzkaller #0 Not tainted
--------------------------------------------
klogd/3611 is trying to acquire lock:
ffffc900143f90d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413
but task is already holding lock:
ffffc900153e40d8 (&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 klogd/3611:
#0: ffffffff8d20a4e8 (syslog_lock){+.+.}-{3:3}, at: syslog_print+0x1bd/0x620 kernel/printk/printk.c:1528
#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: ffffc900153e40d8 (&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: 3611 Comm: klogd 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:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
bpf_trace_run2+0x1fd/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:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
bpf_trace_run3+0x231/0x440 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
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:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212
Code: e8 25 00 00 00 0f 0b 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d e8 0c 16 0d 48 89 de 5b e9 67 8a 56 00 cc cc cc cc cc cc cc <48> 8b 04 24 65 48 8b 0d 74 c5 77 7e 65 8b 15 75 c5 77 7e 81 e2 00
RSP: 0018:ffffc90003277b78 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807c563b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003277d50 R08: ffffffff816e232c R09: fffff5200064ef43
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90003277c60
R13: dffffc0000000000 R14: 00000000000023e2 R15: 0000000000000000
syslog_print+0x3a6/0x620 kernel/printk/printk.c:1556
do_syslog+0x819/0x910 kernel/printk/printk.c:1679
__do_sys_syslog kernel/printk/printk.c:1771 [inline]
__se_sys_syslog kernel/printk/printk.c:1769 [inline]
__x64_sys_syslog+0x78/0x90 kernel/printk/printk.c:1769
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: 0033:0x7f6a08c71fa7
Code: 73 01 c3 48 8b 0d 81 ce 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 ce 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffec9727d38 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007f6a08e104a0 RCX: 00007f6a08c71fa7
RDX: 00000000000003ff RSI: 00007f6a08e104a0 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000007 R09: 49e1d674c2f7aa53
R10: 0000000000000008 R11: 0000000000000206 R12: 00007f6a08e104a0
R13: 00007f6a08e00212 R14: 00007f6a08e104f9 R15: 00007f6a08e104f9
----------------
Code disassembly (best guess):
0: e8 25 00 00 00 call 0x2a
5: 0f 0b ud2
7: 0f 1f 00 nopl (%rax)
a: 53 push %rbx
b: 48 89 fb mov %rdi,%rbx
e: e8 17 00 00 00 call 0x2a
13: 48 8b 3d e8 0c 16 0d mov 0xd160ce8(%rip),%rdi # 0xd160d02
1a: 48 89 de mov %rbx,%rsi
1d: 5b pop %rbx
1e: e9 67 8a 56 00 jmp 0x568a8a
23: cc int3
24: cc int3
25: cc int3
26: cc int3
27: cc int3
28: cc int3
29: cc int3
* 2a: 48 8b 04 24 mov (%rsp),%rax <-- trapping instruction
2e: 65 48 8b 0d 74 c5 77 mov %gs:0x7e77c574(%rip),%rcx # 0x7e77c5aa
35: 7e
36: 65 8b 15 75 c5 77 7e mov %gs:0x7e77c575(%rip),%edx # 0x7e77c5b2
3d: 81 .byte 0x81
3e: e2 00 loop 0x40