============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.5.633/8083 is trying to acquire lock:
ffffc900041b10d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423
but task is already holding lock:
ffffc900041810d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 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
8 locks held by syz.5.633/8083:
#0: ffff88804e530808 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x19f/0x3d0 mm/mmap_lock.c:147
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: do_fault_around mm/memory.c:5530 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: do_read_fault mm/memory.c:5564 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: do_fault mm/memory.c:5707 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: do_pte_missing mm/memory.c:4234 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: handle_pte_fault mm/memory.c:6052 [inline]
#1: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: __handle_mm_fault+0x27b7/0x5440 mm/memory.c:6195
#2: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#2: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#2: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: filemap_map_pages+0x150/0x1740 mm/filemap.c:3747
#3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#3: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x250 mm/pgtable-generic.c:286
#4: ffff888055b04678 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#4: ffff888055b04678 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:401
#5: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#5: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#5: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline]
#5: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4b0 kernel/trace/bpf_trace.c:2298
#6: ffffc900041810d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423
#7: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#7: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#7: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: trace_call_bpf+0xb7/0x850 kernel/trace/bpf_trace.c:-1
stack backtrace:
CPU: 0 UID: 0 PID: 8083 Comm: syz.5.633 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
__bpf_ringbuf_reserve+0x1c7/0x5a0 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_df2ea1bb7efca089+0x36/0x54
bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
__bpf_prog_run include/linux/filter.h:718 [inline]
bpf_prog_run include/linux/filter.h:725 [inline]
bpf_prog_run_array include/linux/bpf.h:2292 [inline]
trace_call_bpf+0x326/0x850 kernel/trace/bpf_trace.c:146
perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:10911
do_perf_trace_contention_end include/trace/events/lock.h:122 [inline]
perf_trace_contention_end+0x253/0x2f0 include/trace/events/lock.h:122
__do_trace_contention_end include/trace/events/lock.h:122 [inline]
trace_contention_end+0x111/0x140 include/trace/events/lock.h:122
__pv_queued_spin_lock_slowpath+0x9f9/0xb60 kernel/locking/qspinlock.c:374
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [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+0x21f/0x290 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
__bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423
____bpf_ringbuf_output kernel/bpf/ringbuf.c:549 [inline]
bpf_ringbuf_output+0x69/0x1f0 kernel/bpf/ringbuf.c:539
bpf_prog_11855e5d4cad9927+0x49/0x56
bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
__bpf_prog_run include/linux/filter.h:718 [inline]
bpf_prog_run include/linux/filter.h:725 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
bpf_trace_run2+0x281/0x4b0 kernel/trace/bpf_trace.c:2298
__bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:38
__do_trace_tlb_flush include/trace/events/tlb.h:38 [inline]
trace_tlb_flush+0x115/0x140 include/trace/events/tlb.h:38
flush_tlb_func+0x5b9/0x6c0 arch/x86/mm/tlb.c:1270
csd_do_func kernel/smp.c:136 [inline]
__flush_smp_call_function_queue+0x370/0xaa0 kernel/smp.c:546
__sysvec_call_function_single+0xa8/0x3d0 arch/x86/kernel/smp.c:271
instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
sysvec_call_function_single+0x9e/0xc0 arch/x86/kernel/smp.c:266
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:xas_next_entry+0x236/0x3d0 include/linux/xarray.h:-1
Code: c9 ff 45 85 f6 74 6b e8 78 7c c9 ff 41 89 ee 41 83 e6 03 bf 02 00 00 00 4c 89 f6 e8 44 81 c9 ff 49 83 fe 02 0f 84 21 01 00 00 <48> 8b 44 24 20 0f b6 04 18 84 c0 0f 85 c9 00 00 00 48 8b 04 24 fe
RSP: 0000:ffffc90003bbf950 EFLAGS: 00000293
RAX: ffffffff81f62fec RBX: dffffc0000000000 RCX: ffff888030115a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffea0001dc3940 R08: ffffea0001dc3937 R09: 1ffffd40003b8726
R10: dffffc0000000000 R11: fffff940003b8727 R12: 1ffff92000777f69
R13: ffffc90003bbfb48 R14: 0000000000000000 R15: ffff88803160e478
next_uptodate_folio+0x32/0x5d0 mm/filemap.c:3595
filemap_map_pages+0x102b/0x1740 mm/filemap.c:3789
do_fault_around mm/memory.c:5531 [inline]
do_read_fault mm/memory.c:5564 [inline]
do_fault mm/memory.c:5707 [inline]
do_pte_missing mm/memory.c:4234 [inline]
handle_pte_fault mm/memory.c:6052 [inline]
__handle_mm_fault+0x34ac/0x5440 mm/memory.c:6195
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f5b12d25df0
Code: 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 b0 ff ff ff 64 48 03 04 25 00 00 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <48> c7 c0 50 fe ff ff 48 c7 c1 c0 ff ff ff 64 48 8b 00 48 8b 00 48
RSP: 002b:00007f5b13c97118 EFLAGS: 00010246
RAX: fffffffffffffeb8 RBX: 00007f5b13c976c0 RCX: 00007f5b12dc3449
RDX: 00007f5b13c97d78 RSI: 0000000000000058 RDI: 00007f5b13c976c0
RBP: 0000000000000000 R08: 00007f5b13c976c0 R09: 00007ffef8cef2b7
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 000000000000000b R14: 00007ffef8cef1d0 R15: 00007ffef8cef2b8
----------------
Code disassembly (best guess):
0: c9 leave
1: ff 45 85 incl -0x7b(%rbp)
4: f6 74 6b e8 divb -0x18(%rbx,%rbp,2)
8: 78 7c js 0x86
a: c9 leave
b: ff 41 89 incl -0x77(%rcx)
e: ee out %al,(%dx)
f: 41 83 e6 03 and $0x3,%r14d
13: bf 02 00 00 00 mov $0x2,%edi
18: 4c 89 f6 mov %r14,%rsi
1b: e8 44 81 c9 ff call 0xffc98164
20: 49 83 fe 02 cmp $0x2,%r14
24: 0f 84 21 01 00 00 je 0x14b
* 2a: 48 8b 44 24 20 mov 0x20(%rsp),%rax <-- trapping instruction
2f: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax
33: 84 c0 test %al,%al
35: 0f 85 c9 00 00 00 jne 0x104
3b: 48 8b 04 24 mov (%rsp),%rax
3f: fe .byte 0xfe