syzbot

8021q: adding VLAN 0 to HW filter on device eth2
==================================================================
BUG: KCSAN: data-race in ___d_drop / __d_lookup

write to 0xffff8881069249d0 of 8 bytes by task 2159 on cpu 1:
 __hlist_bl_del include/linux/list_bl.h:128 [inline]
 ___d_drop+0xa8/0x190 fs/dcache.c:570
 __d_drop fs/dcache.c:577 [inline]
 d_invalidate+0x53/0x1f0 fs/dcache.c:1863
 proc_invalidate_siblings_dcache+0x1c8/0x2b0 fs/proc/inode.c:142
 proc_sys_invalidate_dcache fs/proc/proc_sysctl.c:289 [inline]
 start_unregistering fs/proc/proc_sysctl.c:316 [inline]
 drop_sysctl_table+0xbd/0x270 fs/proc/proc_sysctl.c:1516
 drop_sysctl_table+0x1be/0x270 fs/proc/proc_sysctl.c:1523
 unregister_sysctl_table+0x30/0x50 fs/proc/proc_sysctl.c:1541
 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:177
 xfrm6_net_sysctl_exit net/ipv6/xfrm6_policy.c:236 [inline]
 xfrm6_net_exit+0x3e/0x90 net/ipv6/xfrm6_policy.c:270
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x285/0x420 net/core/net_namespace.c:252
 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881069249d0 of 8 bytes by task 3023 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:396 [inline]
 __d_lookup+0xf8/0x340 fs/dcache.c:2620
 lookup_fast+0x5e/0x320 fs/namei.c:1878
 walk_component fs/namei.c:2278 [inline]
 link_path_walk+0x523/0xdd0 fs/namei.c:2656
 path_openat+0x1ac/0x2000 fs/namei.c:4855
 do_file_open+0x16c/0x290 fs/namei.c:4888
 do_sys_openat2+0xa0/0x130 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1412
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8881069243c8 -> 0xffff888107e79308

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3023 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================
8021q: adding VLAN 0 to HW filter on device eth3
8021q: adding VLAN 0 to HW filter on device eth4
8021q: adding VLAN 0 to HW filter on device eth5
8021q: adding VLAN 0 to HW filter on device eth6
8021q: adding VLAN 0 to HW filter on device eth8
8021q: adding VLAN 0 to HW filter on device eth7
8021q: adding VLAN 0 to HW filter on device eth9
8021q: adding VLAN 0 to HW filter on device eth10
8021q: adding VLAN 0 to HW filter on device eth11
8021q: adding VLAN 0 to HW filter on device eth12
8021q: adding VLAN 0 to HW filter on device eth13
8021q: adding VLAN 0 to HW filter on device eth14
8021q: adding VLAN 0 to HW filter on device eth15
8021q: adding VLAN 0 to HW filter on device eth16
8021q: adding VLAN 0 to HW filter on device eth17
8021q: adding VLAN 0 to HW filter on device eth18
8021q: adding VLAN 0 to HW filter on device eth20
8021q: adding VLAN 0 to HW filter on device eth19
8021q: adding VLAN 0 to HW filter on device eth21
8021q: adding VLAN 0 to HW filter on device eth22
8021q: adding VLAN 0 to HW filter on device eth23
8021q: adding VLAN 0 to HW filter on device eth24