======================================================
WARNING: possible circular locking dependency detected
6.1.112-syzkaller #0 Not tainted
------------------------------------------------------
syz.0.1206/7627 is trying to acquire lock:
ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline]
ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline]
ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402

but task is already holding lock:
ffff8880b8f28358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&base->lock){-.-.}-{2:2}:
       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
       lock_timer_base+0x120/0x260 kernel/time/timer.c:999
       __mod_timer+0x1cb/0xee0 kernel/time/timer.c:1072
       queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1704
       queue_delayed_work include/linux/workqueue.h:527 [inline]
       schedule_delayed_monitor_work kernel/rcu/tree.c:3172 [inline]
       kvfree_call_rcu+0x520/0x8c0 kernel/rcu/tree.c:3428
       rtnl_register_internal+0x489/0x580 net/core/rtnetlink.c:260
       rtnl_register+0x32/0x70 net/core/rtnetlink.c:310
       ip_rt_init+0x335/0x3c7 net/ipv4/route.c:3763
       ip_init+0xa/0x14 net/ipv4/ip_output.c:1767
       inet_init+0x2ae/0x3c0 net/ipv4/af_inet.c:2035
       do_one_initcall+0x265/0x8f0 init/main.c:1298
       do_initcall_level+0x157/0x207 init/main.c:1371
       do_initcalls+0x49/0x86 init/main.c:1387
       kernel_init_freeable+0x45c/0x60f init/main.c:1626
       kernel_init+0x19/0x290 init/main.c:1514
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 (krc.lock){..-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __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:2991 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline]
       kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402
       trie_delete_elem+0x53a/0x690 kernel/bpf/lpm_trie.c:532
       bpf_prog_d46ba5bef82912c0+0x3d/0x41
       bpf_dispatcher_nop_func include/linux/bpf.h:989 [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:2273 [inline]
       bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2313
       trace_timer_start include/trace/events/timer.h:53 [inline]
       enqueue_timer+0x440/0x600 kernel/time/timer.c:609
       __mod_timer+0x92b/0xee0
       call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504
       expire_timers kernel/time/timer.c:1549 [inline]
       __run_timers+0x67c/0x890 kernel/time/timer.c:1820
       run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
       handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571
       __do_softirq kernel/softirq.c:605 [inline]
       invoke_softirq kernel/softirq.c:445 [inline]
       __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654
       irq_exit_rcu+0x5/0x20 kernel/softirq.c:666
       sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
       asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
       lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
       fs_reclaim_acquire+0xaa/0x120 mm/page_alloc.c:4698
       might_alloc include/linux/sched/mm.h:271 [inline]
       slab_pre_alloc_hook+0x2a/0x300 mm/slab.h:710
       slab_alloc_node mm/slub.c:3318 [inline]
       __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
       kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
       kmalloc include/linux/slab.h:557 [inline]
       kzalloc include/linux/slab.h:693 [inline]
       do_check_common+0x148/0xca90 kernel/bpf/verifier.c:14898
       do_check_main kernel/bpf/verifier.c:15016 [inline]
       bpf_check+0x65a2/0x16140 kernel/bpf/verifier.c:15593
       bpf_prog_load+0x12df/0x1bb0 kernel/bpf/syscall.c:2646
       __sys_bpf+0x382/0x6c0 kernel/bpf/syscall.c:5020
       __do_sys_bpf kernel/bpf/syscall.c:5124 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5122 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122
       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

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 ***

5 locks held by syz.0.1206/7627:
 #0: ffffffff8d4054e0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:271 [inline]
 #0: ffffffff8d4054e0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook+0x2a/0x300 mm/slab.h:710
 #1: ffffffff8d4176a0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire+0x8e/0x120 mm/page_alloc.c:4698
 #2: ffffc900001e0bc0 ((&app->join_timer)#2){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501
 #3: ffff8880b8f28358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999
 #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline]
 #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2313

stack backtrace:
CPU: 1 PID: 7627 Comm: syz.0.1206 Not tainted 6.1.112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __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:2991 [inline]
 add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline]
 kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402
 trie_delete_elem+0x53a/0x690 kernel/bpf/lpm_trie.c:532
 bpf_prog_d46ba5bef82912c0+0x3d/0x41
 bpf_dispatcher_nop_func include/linux/bpf.h:989 [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:2273 [inline]
 bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2313
 trace_timer_start include/trace/events/timer.h:53 [inline]
 enqueue_timer+0x440/0x600 kernel/time/timer.c:609
 __mod_timer+0x92b/0xee0
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x67c/0x890 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571
 __do_softirq kernel/softirq.c:605 [inline]
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 3f ac 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90004a0ed00 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000941dac RCX: ffffffff816b3d32
RDX: dffffc0000000000 RSI: ffffffff8b0c14c0 RDI: ffffffff8b5d7180
RBP: ffffc90004a0ee50 R08: dffffc0000000000 R09: fffffbfff223ba47
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000941da8
R13: dffffc0000000000 R14: ffffc90004a0ed60 R15: 0000000000000246
 fs_reclaim_acquire+0xaa/0x120 mm/page_alloc.c:4698
 might_alloc include/linux/sched/mm.h:271 [inline]
 slab_pre_alloc_hook+0x2a/0x300 mm/slab.h:710
 slab_alloc_node mm/slub.c:3318 [inline]
 __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc include/linux/slab.h:693 [inline]
 do_check_common+0x148/0xca90 kernel/bpf/verifier.c:14898
 do_check_main kernel/bpf/verifier.c:15016 [inline]
 bpf_check+0x65a2/0x16140 kernel/bpf/verifier.c:15593
 bpf_prog_load+0x12df/0x1bb0 kernel/bpf/syscall.c:2646
 __sys_bpf+0x382/0x6c0 kernel/bpf/syscall.c:5020
 __do_sys_bpf kernel/bpf/syscall.c:5124 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5122 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122
 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: 0033:0x7f051917dff9
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:00007f0519ec2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f0519335f80 RCX: 00007f051917dff9
RDX: 0000000000000094 RSI: 00000000200007c0 RDI: 0000000000000005
RBP: 00007f05191f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0519335f80 R15: 00007ffea8d819c8
 </TASK>
----------------
Code disassembly (best guess):
   0:	2b 00                	sub    (%rax),%eax
   2:	74 08                	je     0xc
   4:	4c 89 f7             	mov    %r14,%rdi
   7:	e8 3f ac 77 00       	call   0x77ac4b
   c:	f6 44 24 61 02       	testb  $0x2,0x61(%rsp)
  11:	0f 85 84 01 00 00    	jne    0x19b
  17:	41 f7 c7 00 02 00 00 	test   $0x200,%r15d
  1e:	74 01                	je     0x21
  20:	fb                   	sti
  21:	48 c7 44 24 40 0e 36 	movq   $0x45e0360e,0x40(%rsp)
  28:	e0 45
* 2a:	4b c7 44 25 00 00 00 	movq   $0x0,0x0(%r13,%r12,1) <-- trapping instruction
  31:	00 00
  33:	43 c7 44 25 09 00 00 	movl   $0x0,0x9(%r13,%r12,1)
  3a:	00 00
  3c:	43                   	rex.XB
  3d:	c7                   	.byte 0xc7
  3e:	44                   	rex.R
  3f:	25                   	.byte 0x25