======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.306/5476 is trying to acquire lock:
ffff8880773d5238 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x710 kernel/bpf/lpm_trie.c:467

but task is already holding lock:
ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&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:3629
       rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:225
       rtnl_register+0x2e/0x70 net/core/rtnetlink.c:275
       ip_rt_init+0x2e0/0x3a0 net/ipv4/route.c:3798
       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:1316
       do_initcall_level+0x137/0x1f0 init/main.c:1389
       do_initcalls+0x4b/0x90 init/main.c:1405
       kernel_init_freeable+0x3ce/0x560 init/main.c:1629
       kernel_init+0x19/0x1b0 init/main.c:1520
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #1 (krc.lock){..-.}-{2:2}:
       __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:3203 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3510 [inline]
       kvfree_call_rcu+0x186/0x7c0 kernel/rcu/tree.c:3601
       trie_delete_elem+0x58c/0x710 kernel/bpf/lpm_trie.c:-1
       0xffffffffa00183aa
       bpf_dispatcher_nop_func include/linux/bpf.h:888 [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
       __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138
       trace_kmem_cache_free include/trace/events/kmem.h:138 [inline]
       kmem_cache_free+0x1e7/0x210 mm/slub.c:3521
       putname fs/namei.c:271 [inline]
       kern_path+0x135/0x190 fs/namei.c:2592
       tomoyo_realpath_nofollow+0x88/0x100 security/tomoyo/realpath.c:308
       tomoyo_find_next_domain+0x24e/0x1a60 security/tomoyo/domain.c:726
       tomoyo_bprm_check_security+0xdd/0x120 security/tomoyo/tomoyo.c:101
       security_bprm_check+0x5e/0x90 security/security.c:868
       search_binary_handler fs/exec.c:1730 [inline]
       exec_binprm fs/exec.c:1783 [inline]
       bprm_execve+0x9f7/0x17d0 fs/exec.c:1852
       kernel_execve+0x82a/0x900 fs/exec.c:2013
       call_usermodehelper_exec_async+0x207/0x350 kernel/umh.c:112
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 (&trie->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_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_c0188993c79ab9c8+0x3d/0x340
       bpf_dispatcher_nop_func include/linux/bpf.h:888 [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_join_timer_arm net/802/mrp.c:596 [inline]
       mrp_join_timer+0x142/0x180 net/802/mrp.c:611
       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:576
       __do_softirq kernel/softirq.c:610 [inline]
       invoke_softirq kernel/softirq.c:450 [inline]
       __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
       irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
       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
       lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
       __might_fault+0xb3/0x110 mm/memory.c:5357
       _copy_from_user+0x29/0x170 lib/usercopy.c:14
       copy_from_user include/linux/uaccess.h:192 [inline]
       __copy_msghdr_from_user net/socket.c:2328 [inline]
       copy_msghdr_from_user net/socket.c:2379 [inline]
       recvmsg_copy_msghdr net/socket.c:2631 [inline]
       ___sys_recvmsg+0x129/0x4f0 net/socket.c:2703
       do_recvmmsg+0x344/0x7a0 net/socket.c:2801
       __sys_recvmmsg net/socket.c:2880 [inline]
       __do_sys_recvmmsg net/socket.c:2903 [inline]
       __se_sys_recvmmsg net/socket.c:2896 [inline]
       __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2896
       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:
  &trie->lock --> krc.lock --> &base->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&base->lock);
                               lock(krc.lock);
                               lock(&base->lock);
  lock(&trie->lock);

 *** DEADLOCK ***

5 locks held by syz.3.306/5476:
 #0: ffff88807bd0b228 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x90/0x110 mm/memory.c:5356
 #1: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
 #1: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
 #2: ffff888061d434c8 (&app->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
 #2: ffff888061d434c8 (&app->lock){+.-.}-{2:2}, at: mrp_join_timer+0xd2/0x180 net/802/mrp.c:609
 #3: ffff8880b91280d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
 #4: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312

stack backtrace:
CPU: 1 PID: 5476 Comm: syz.3.306 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <IRQ>
 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_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_c0188993c79ab9c8+0x3d/0x340
 bpf_dispatcher_nop_func include/linux/bpf.h:888 [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_join_timer_arm net/802/mrp.c:596 [inline]
 mrp_join_timer+0x142/0x180 net/802/mrp.c:611
 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:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0000:ffffc90003a87900 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: a64e431acebf2300
RDX: 0000000000000000 RSI: ffffffff8a0b2f00 RDI: ffffffff8a59e580
RBP: ffffc90003a87a20 R08: dffffc0000000000 R09: fffffbfff1ff7c1f
R10: fffffbfff1ff7c1f R11: 1ffffffff1ff7c1e R12: ffff88807bd0b228
R13: 1ffff92000750f2c R14: 0000000000000246 R15: dffffc0000000000
 __might_fault+0xb3/0x110 mm/memory.c:5357
 _copy_from_user+0x29/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:192 [inline]
 __copy_msghdr_from_user net/socket.c:2328 [inline]
 copy_msghdr_from_user net/socket.c:2379 [inline]
 recvmsg_copy_msghdr net/socket.c:2631 [inline]
 ___sys_recvmsg+0x129/0x4f0 net/socket.c:2703
 do_recvmmsg+0x344/0x7a0 net/socket.c:2801
 __sys_recvmmsg net/socket.c:2880 [inline]
 __do_sys_recvmmsg net/socket.c:2903 [inline]
 __se_sys_recvmmsg net/socket.c:2896 [inline]
 __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2896
 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: 0033:0x7f8d2c760749
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:00007f8d2a9a6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f8d2c9b7090 RCX: 00007f8d2c760749
RDX: 03fffffffffffcb5 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f8d2c7e4f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8d2c9b7128 R14: 00007f8d2c9b7090 R15: 00007fff4de4d1d8
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 9c 8f 84 24 80 00 	add    %bl,0x802484(%rdi,%rcx,4)
   7:	00 00                	add    %al,(%rax)
   9:	f6 84 24 81 00 00 00 	testb  $0x2,0x81(%rsp)
  10:	02
  11:	0f 85 f6 00 00 00    	jne    0x10d
  17:	41 f7 c6 00 02 00 00 	test   $0x200,%r14d
  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 44 3d 00 00 00 	movq   $0x0,0x0(%r13,%r15,1) <-- trapping instruction
  31:	00 00
  33:	66 43 c7 44 3d 09 00 	movw   $0x0,0x9(%r13,%r15,1)
  3a:	00
  3b:	43                   	rex.XB
  3c:	c6                   	.byte 0xc6
  3d:	44                   	rex.R
  3e:	3d                   	.byte 0x3d
  3f:	0b                   	.byte 0xb