======================================================
WARNING: possible circular locking dependency detected
5.15.184-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.27/4334 is trying to acquire lock:
ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
ffff8880b9027e78 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597
but task is already holding lock:
ffff888063dea5b8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&trie->lock){..-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
bpf_prog_2c29ac5cdc6b1842+0x3a/0x660
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
internal_add_timer kernel/time/timer.c:611 [inline]
__mod_timer+0x8e1/0xd20 kernel/time/timer.c:1062
schedule_timeout+0x157/0x280 kernel/time/timer.c:1913
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
-> #1 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:946
__mod_timer+0x117/0xd20 kernel/time/timer.c:1019
queue_delayed_work_on+0x126/0x1e0 kernel/workqueue.c:1715
queue_delayed_work include/linux/workqueue.h:527 [inline]
schedule_delayed_work include/linux/workqueue.h:631 [inline]
kvfree_call_rcu+0x4a9/0x7c0 kernel/rcu/tree.c:3625
rtnl_register_internal+0x44e/0x540 net/core/rtnetlink.c:223
rtnl_register+0x2e/0x70 net/core/rtnetlink.c:273
ip_rt_init+0x2e0/0x3a0 net/ipv4/route.c:3791
ip_init+0xa/0x20 net/ipv4/ip_output.c:1749
inet_init+0x28b/0x3a0 net/ipv4/af_inet.c:2007
do_one_initcall+0x1ee/0x680 init/main.c:1302
do_initcall_level+0x137/0x1f0 init/main.c:1375
do_initcalls+0x4b/0x90 init/main.c:1391
kernel_init_freeable+0x3ce/0x560 init/main.c:1615
kernel_init+0x19/0x1b0 init/main.c:1506
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
-> #0 (krc.lock){..-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597
trie_delete_elem+0x58c/0x710 kernel/bpf/lpm_trie.c:-1
bpf_prog_2c29ac5cdc6b1842+0x3a/0x660
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
internal_add_timer kernel/time/timer.c:611 [inline]
__mod_timer+0x8e1/0xd20 kernel/time/timer.c:1062
mrp_periodic_timer_arm net/802/mrp.c:617 [inline]
mrp_periodic_timer+0x1c5/0x200 net/802/mrp.c:629
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:558
__do_softirq kernel/softirq.c:592 [inline]
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:641
irq_exit_rcu+0x5/0x20 kernel/softirq.c:653
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
trie_update_elem+0x6c8/0xc50 kernel/bpf/lpm_trie.c:447
bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221
map_update_elem+0x626/0x770 kernel/bpf/syscall.c:1188
__sys_bpf+0x3fb/0x670 kernel/bpf/syscall.c:4639
__do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
other info that might help us debug this:
Chain exists of:
krc.lock --> &base->lock --> &trie->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&trie->lock);
lock(&base->lock);
lock(&trie->lock);
lock(krc.lock);
*** DEADLOCK ***
6 locks held by syz.1.27/4334:
#0: ffffffff8c11c060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#1: ffffc90000007be0 ((&app->periodic_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#1: ffffc90000007be0 ((&app->periodic_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
#2: ffff888079a360c8 (&app->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#2: ffff888079a360c8 (&app->lock){+.-.}-{2:2}, at: mrp_periodic_timer+0x2c/0x200 net/802/mrp.c:625
#3: ffff8880b9028098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
#4: ffffffff8c11c060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#5: ffff888063dea5b8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467
stack backtrace:
CPU: 0 PID: 4334 Comm: syz.1.27 Not tainted 5.15.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3597
trie_delete_elem+0x58c/0x710 kernel/bpf/lpm_trie.c:-1
bpf_prog_2c29ac5cdc6b1842+0x3a/0x660
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
internal_add_timer kernel/time/timer.c:611 [inline]
__mod_timer+0x8e1/0xd20 kernel/time/timer.c:1062
mrp_periodic_timer_arm net/802/mrp.c:617 [inline]
mrp_periodic_timer+0x1c5/0x200 net/802/mrp.c:629
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:558
__do_softirq kernel/softirq.c:592 [inline]
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:641
irq_exit_rcu+0x5/0x20 kernel/softirq.c:653
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 6e 53 d3 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 46 d3 a6 f7 65 8b 05 b7 e3 57 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900031efb60 EFLAGS: 00000206
RAX: 7527dfacc0bc9e00 RBX: 0000000000000a06 RCX: 7527dfacc0bc9e00
RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: 0000000000000001
RBP: ffffc900031efbe8 R08: dffffc0000000000 R09: ffffed100c7bd4b5
R10: ffffed100c7bd4b5 R11: 1ffff1100c7bd4b4 R12: dffffc0000000000
R13: ffff888063dea400 R14: ffff888063dea5a0 R15: 1ffff9200063df6c
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
trie_update_elem+0x6c8/0xc50 kernel/bpf/lpm_trie.c:447
bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221
map_update_elem+0x626/0x770 kernel/bpf/syscall.c:1188
__sys_bpf+0x3fb/0x670 kernel/bpf/syscall.c:4639
__do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2fe81e3969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2fe604b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2fe840afa0 RCX: 00007f2fe81e3969
RDX: 0000000000000020 RSI: 0000200000000240 RDI: 0000000000000002
RBP: 00007f2fe8265ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2fe840afa0 R15: 00007fff19e4d6f8
----------------
Code disassembly (best guess):
0: 74 05 je 0x7
2: e8 6e 53 d3 f7 call 0xf7d35375
7: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp)
e: 00 00
10: 9c pushf
11: 8f 44 24 20 pop 0x20(%rsp)
15: f6 44 24 21 02 testb $0x2,0x21(%rsp)
1a: 75 4b jne 0x67
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 46 d3 a6 f7 call 0xf7a6d375 <-- trapping instruction
2f: 65 8b 05 b7 e3 57 76 mov %gs:0x7657e3b7(%rip),%eax # 0x7657e3ed
36: 85 c0 test %eax,%eax
38: 74 3c je 0x76
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss