syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.134-syzkaller #0 Not tainted
------------------------------------------------------
udevd/4246 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:
ffff8880b8f29418 (&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:3789
       ip_init+0xa/0x14 net/ipv4/ip_output.c:1770
       inet_init+0x2ae/0x3c0 net/ipv4/af_inet.c:2033
       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:545
       bpf_prog_1db1603a7cfa36fb+0x3d/0x41
       bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
       bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2324
       trace_timer_start include/trace/events/timer.h:53 [inline]
       enqueue_timer+0x440/0x600 kernel/time/timer.c:609
       __mod_timer+0x92b/0xee0 kernel/time/timer.c:-1
       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
       handle_softirqs+0x2ee/0xa40 kernel/softirq.c:578
       __do_softirq kernel/softirq.c:612 [inline]
       invoke_softirq kernel/softirq.c:452 [inline]
       __irq_exit_rcu+0x157/0x240 kernel/softirq.c:661
       irq_exit_rcu+0x5/0x20 kernel/softirq.c:673
       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
       find_stack lib/stackdepot.c:304 [inline]
       __stack_depot_save+0x172/0x470 lib/stackdepot.c:452
       kasan_save_stack mm/kasan/common.c:46 [inline]
       kasan_set_track+0x60/0x70 mm/kasan/common.c:52
       __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
       kasan_slab_alloc include/linux/kasan.h:201 [inline]
       slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
       slab_alloc_node mm/slub.c:3398 [inline]
       slab_alloc mm/slub.c:3406 [inline]
       __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
       kmem_cache_alloc_lru+0x10c/0x2d0 mm/slub.c:3429
       __d_alloc+0x31/0x760 fs/dcache.c:1774
       d_alloc fs/dcache.c:1854 [inline]
       d_alloc_parallel+0xdd/0x1590 fs/dcache.c:2645
       lookup_open fs/namei.c:3407 [inline]
       open_last_lookups fs/namei.c:3550 [inline]
       path_openat+0x90a/0x2e60 fs/namei.c:3780
       do_filp_open+0x230/0x480 fs/namei.c:3810
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_openat fs/open.c:1350 [inline]
       __se_sys_openat fs/open.c:1345 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1345
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0x80 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 ***

4 locks held by udevd/4246:
 #0: ffff888074093900 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff888074093900 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: open_last_lookups fs/namei.c:3549 [inline]
 #0: ffff888074093900 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: path_openat+0x7a7/0x2e60 fs/namei.c:3780
 #1: ffffc900001e0be0 ((&tcp_orphan_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501
 #2: ffff8880b8f29418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999
 #3: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #3: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
 #3: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2324

stack backtrace:
CPU: 1 PID: 4246 Comm: udevd Not tainted 6.1.134-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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:545
 bpf_prog_1db1603a7cfa36fb+0x3d/0x41
 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
 bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2324
 trace_timer_start include/trace/events/timer.h:53 [inline]
 enqueue_timer+0x440/0x600 kernel/time/timer.c:609
 __mod_timer+0x92b/0xee0 kernel/time/timer.c:-1
 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
 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0x157/0x240 kernel/softirq.c:661
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:673
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:find_stack lib/stackdepot.c:305 [inline]
RIP: 0010:__stack_depot_save+0x172/0x470 lib/stackdepot.c:452
Code: 04 13 8b 1d 24 84 04 13 44 21 eb 48 89 44 24 10 4c 8b 34 d8 4c 89 c5 41 89 ec eb 03 4d 8b 36 4d 85 f6 74 2a 45 39 6e 08 75 f2 <41> 39 6e 0c 75 ec 31 c0 49 8b 0c c7 49 3b 4c c6 18 75 df 48 ff c0
RSP: 0018:ffffc90003bb7358 EFLAGS: 00000246
RAX: ffff88823b400000 RBX: 0000000000095ad0 RCX: 0000000074f5b41d
RDX: ffffc90003bb7414 RSI: 0000000000000003 RDI: 0000000000000cc0
RBP: 000000000000000c R08: 000000000000000c R09: 0000000000000001
R10: 0000000000000000 R11: dffffc0000000001 R12: 000000000000000c
R13: 0000000010b95ad0 R14: ffff88807e113000 R15: ffffc90003bb73c0
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x60/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc_lru+0x10c/0x2d0 mm/slub.c:3429
 __d_alloc+0x31/0x760 fs/dcache.c:1774
 d_alloc fs/dcache.c:1854 [inline]
 d_alloc_parallel+0xdd/0x1590 fs/dcache.c:2645
 lookup_open fs/namei.c:3407 [inline]
 open_last_lookups fs/namei.c:3550 [inline]
 path_openat+0x90a/0x2e60 fs/namei.c:3780
 do_filp_open+0x230/0x480 fs/namei.c:3810
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdd179169a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffffadeb2a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007fdd179169a4
RDX: 0000000000080000 RSI: 00007ffffadeb3d8 RDI: 00000000ffffff9c
RBP: 00007ffffadeb3d8 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 000055d0967
----------------
Code disassembly (best guess):
   0:	04 13                	add    $0x13,%al
   2:	8b 1d 24 84 04 13    	mov    0x13048424(%rip),%ebx        # 0x1304842c
   8:	44 21 eb             	and    %r13d,%ebx
   b:	48 89 44 24 10       	mov    %rax,0x10(%rsp)
  10:	4c 8b 34 d8          	mov    (%rax,%rbx,8),%r14
  14:	4c 89 c5             	mov    %r8,%rbp
  17:	41 89 ec             	mov    %ebp,%r12d
  1a:	eb 03                	jmp    0x1f
  1c:	4d 8b 36             	mov    (%r14),%r14
  1f:	4d 85 f6             	test   %r14,%r14
  22:	74 2a                	je     0x4e
  24:	45 39 6e 08          	cmp    %r13d,0x8(%r14)
  28:	75 f2                	jne    0x1c
* 2a:	41 39 6e 0c          	cmp    %ebp,0xc(%r14) <-- trapping instruction
  2e:	75 ec                	jne    0x1c
  30:	31 c0                	xor    %eax,%eax
  32:	49 8b 0c c7          	mov    (%r15,%rax,8),%rcx
  36:	49 3b 4c c6 18       	cmp    0x18(%r14,%rax,8),%rcx
  3b:	75 df                	jne    0x1c
  3d:	48 ff c0             	inc    %rax