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BUG: KCSAN: data-race in __d_lookup / __d_rehash

write to 0xffff888106126190 of 8 bytes by task 3268 on cpu 1:
 hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
 __d_rehash+0xa9/0x210 fs/dcache.c:2412
 __d_add+0x373/0x4a0 fs/dcache.c:2627
 d_splice_alias+0xd6/0x270 fs/dcache.c:3018
 proc_sys_lookup+0x386/0x440 fs/proc/proc_sysctl.c:534
 lookup_open fs/namei.c:3556 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0xc5f/0x1f10 fs/namei.c:3883
 do_filp_open+0xf7/0x200 fs/namei.c:3913
 do_sys_openat2+0xab/0x120 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1442
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106126190 of 8 bytes by task 3266 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:354 [inline]
 __d_lookup+0xf1/0x370 fs/dcache.c:2324
 lookup_fast+0x4c/0x2a0 fs/namei.c:1676
 open_last_lookups fs/namei.c:3615 [inline]
 path_openat+0x466/0x1f10 fs/namei.c:3883
 do_filp_open+0xf7/0x200 fs/namei.c:3913
 do_sys_openat2+0xab/0x120 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1442
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8882379da1a8 -> 0xffff888106126b48

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3266 Comm: syz-executor Not tainted 6.11.0-rc2-syzkaller-00194-gafdab700f65e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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