syzbot

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BUG: KCSAN: data-race in d_lru_add / step_into

write to 0xffff88811ce1f900 of 4 bytes by task 19180 on cpu 0:
 d_lru_add+0x45/0xe0 fs/dcache.c:426
 retain_dentry fs/dcache.c:712 [inline]
 fast_dput+0x261/0x2b0 fs/dcache.c:799
 dput+0x24/0xc0 fs/dcache.c:839
 path_put fs/namei.c:562 [inline]
 terminate_walk+0xf2/0x270 fs/namei.c:686
 path_openat+0x1923/0x1d40 fs/namei.c:3799
 do_filp_open+0xf6/0x200 fs/namei.c:3825
 do_sys_openat2+0xab/0x110 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_openat fs/open.c:1435 [inline]
 __se_sys_openat fs/open.c:1430 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1430
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88811ce1f900 of 4 bytes by task 19181 on cpu 1:
 __follow_mount_rcu fs/namei.c:1486 [inline]
 handle_mounts fs/namei.c:1537 [inline]
 step_into+0xe7/0x800 fs/namei.c:1839
 walk_component fs/namei.c:2007 [inline]
 link_path_walk+0x4d8/0x7e0 fs/namei.c:2328
 path_openat+0x1a0/0x1d40 fs/namei.c:3794
 do_filp_open+0xf6/0x200 fs/namei.c:3825
 do_sys_openat2+0xab/0x110 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_openat fs/open.c:1435 [inline]
 __se_sys_openat fs/open.c:1430 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1430
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0020000c -> 0x0028004c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19181 Comm: syz-executor.3 Not tainted 6.8.0-rc3-syzkaller-00010-g6d280f4d760e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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