======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.208/4617 is trying to acquire lock:
ffff8880b8e28218 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
ffff8880b8e28218 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
ffff8880b8e28218 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18b/0x890 kernel/rcu/tree.c:3406
but task is already holding lock:
ffff8880b8e28458 (&base->lock){-.-.}-{2:2}, at: __run_timers+0x127/0x810 kernel/time/timer.c:2005
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:999
__mod_timer+0xf9/0xd20 kernel/time/timer.c:1080
queue_delayed_work_on+0x12d/0x1f0 kernel/workqueue.c:1704
queue_delayed_work include/linux/workqueue.h:527 [inline]
schedule_delayed_monitor_work kernel/rcu/tree.c:3176 [inline]
kvfree_call_rcu+0x4fb/0x890 kernel/rcu/tree.c:3432
rtnl_register_internal+0x485/0x590 net/core/rtnetlink.c:260
rtnl_register+0x2e/0x70 net/core/rtnetlink.c:310
ip_rt_init+0x324/0x3b6 net/ipv4/route.c:3753
ip_init+0xa/0x14 net/ipv4/ip_output.c:1779
inet_init+0x2bd/0x3cf net/ipv4/af_inet.c:2033
do_one_initcall+0x257/0x800 init/main.c:1309
do_initcall_level+0x13d/0x1ed init/main.c:1382
do_initcalls+0x4b/0x8a init/main.c:1398
kernel_init_freeable+0x401/0x5ab init/main.c:1637
kernel_init+0x19/0x1b0 init/main.c:1525
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
-> #0 (krc.lock){..-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3830 [inline]
__lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
kvfree_call_rcu+0x18b/0x890 kernel/rcu/tree.c:3406
trie_delete_elem+0x4e9/0x620 kernel/bpf/lpm_trie.c:543
bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:607 [inline]
bpf_prog_run include/linux/filter.h:614 [inline]
bpf_prog_run_array include/linux/bpf.h:1668 [inline]
trace_call_bpf+0x322/0x6b0 kernel/trace/bpf_trace.c:135
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10027
perf_trace_timer_class+0x264/0x2e0 include/trace/events/timer.h:12
trace_timer_cancel include/trace/events/timer.h:138 [inline]
debug_deactivate kernel/time/timer.c:832 [inline]
detach_timer+0x2c0/0x350 kernel/time/timer.c:878
expire_timers kernel/time/timer.c:1735 [inline]
__run_timers+0x4ed/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
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
lock_release+0x5ab/0x920 kernel/locking/lockdep.c:5700
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
dentry_unlink_inode+0x186/0x3b0 fs/dcache.c:398
__dentry_kill+0x412/0x630 fs/dcache.c:611
dentry_kill+0xb8/0x290 fs/dcache.c:-1
dput+0xfa/0x1d0 fs/dcache.c:918
__fput+0x597/0x8b0 fs/file_table.c:328
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&base->lock);
lock(krc.lock);
lock(&base->lock);
lock(krc.lock);
*** DEADLOCK ***
3 locks held by syz.0.208/4617:
#0: ffff888140cce410 (&sb->s_type->i_lock_key#15){+.+.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline]
#0: ffff888140cce410 (&sb->s_type->i_lock_key#15){+.+.}-{2:2}, at: dentry_kill+0x4b/0x290 fs/dcache.c:721
#1: ffff8880b8e28458 (&base->lock){-.-.}-{2:2}, at: __run_timers+0x127/0x810 kernel/time/timer.c:2005
#2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbf/0x6b0 kernel/trace/bpf_trace.c:134
stack backtrace:
CPU: 0 PID: 4617 Comm: syz.0.208 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3830 [inline]
__lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
krc_this_cpu_lock kernel/rcu/tree.c:2995 [inline]
add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3315 [inline]
kvfree_call_rcu+0x18b/0x890 kernel/rcu/tree.c:3406
trie_delete_elem+0x4e9/0x620 kernel/bpf/lpm_trie.c:543
bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:607 [inline]
bpf_prog_run include/linux/filter.h:614 [inline]
bpf_prog_run_array include/linux/bpf.h:1668 [inline]
trace_call_bpf+0x322/0x6b0 kernel/trace/bpf_trace.c:135
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10027
perf_trace_timer_class+0x264/0x2e0 include/trace/events/timer.h:12
trace_timer_cancel include/trace/events/timer.h:138 [inline]
debug_deactivate kernel/time/timer.c:832 [inline]
detach_timer+0x2c0/0x350 kernel/time/timer.c:878
expire_timers kernel/time/timer.c:1735 [inline]
__run_timers+0x4ed/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
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:lock_release+0x5ab/0x920 kernel/locking/lockdep.c:5700
Code: 00 00 00 f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 2f 04 f8 75 70 f7 44 24 50 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 43 c7 44 2f 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900040e7b60 EFLAGS: 00000206
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: b5291e8ea04f3b00
RDX: 00000000ffffffff RSI: ffffffff8a8c2920 RDI: ffffffff8adf5de0
RBP: ffffc900040e7c80 R08: dffffc0000000000 R09: 1ffffffff2161e4f
R10: dffffc0000000000 R11: fffffbfff2161e50 R12: ffff888079f3e4e0
R13: dffffc0000000000 R14: ffff888079f3e4d0 R15: 1ffff9200081cf78
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
dentry_unlink_inode+0x186/0x3b0 fs/dcache.c:398
__dentry_kill+0x412/0x630 fs/dcache.c:611
dentry_kill+0xb8/0x290 fs/dcache.c:-1
dput+0xfa/0x1d0 fs/dcache.c:918
__fput+0x597/0x8b0 fs/file_table.c:328
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ffa96d9de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef26bfb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffef26bfc70 RCX: 00007ffa96d9de99
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001be5b R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2db20000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffa97025fac R14: 00007ffa97025fa8 R15: 00007ffa97025fa0
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 f7 add %dh,%bh
4: 84 24 80 test %ah,(%rax,%rax,4)
7: 00 00 add %al,(%rax)
9: 00 00 add %al,(%rax)
b: 02 00 add (%rax),%al
d: 00 43 c6 add %al,-0x3a(%rbx)
10: 44 2f rex.R (bad)
12: 04 f8 add $0xf8,%al
14: 75 70 jne 0x86
16: f7 44 24 50 00 02 00 testl $0x200,0x50(%rsp)
1d: 00
1e: 74 01 je 0x21
20: fb sti
21: 48 c7 44 24 60 0e 36 movq $0x45e0360e,0x60(%rsp)
28: e0 45
* 2a: 4b c7 04 2f 00 00 00 movq $0x0,(%r15,%r13,1) <-- trapping instruction
31: 00
32: 43 c7 44 2f 08 00 00 movl $0x0,0x8(%r15,%r13,1)
39: 00 00
3b: 65 gs
3c: 48 rex.W
3d: 8b .byte 0x8b
3e: 04 25 add $0x25,%al