syzbot

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BUG: KCSAN: data-race in link_path_walk / shrink_dentry_list

write to 0xffff8881263d9f00 of 4 bytes by task 18699 on cpu 1:
 d_shrink_add fs/dcache.c:429 [inline]
 __dput_to_list fs/dcache.c:893 [inline]
 shrink_dentry_list+0x45c/0x530 fs/dcache.c:1140
 shrink_dcache_sb+0x10d/0x1c0 fs/dcache.c:1261
 reconfigure_super+0x267/0x4d0 fs/super.c:940
 do_remount fs/namespace.c:2612 [inline]
 do_mount+0x1384/0x1c00 fs/namespace.c:3191
 __do_sys_mount fs/namespace.c:3410 [inline]
 __se_sys_mount+0xd3/0x100 fs/namespace.c:3387
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3387
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881263d9f00 of 4 bytes by task 18708 on cpu 0:
 link_path_walk+0x334/0x730 fs/namei.c:2145
 path_openat+0x199/0x20e0 fs/namei.c:3356
 do_filp_open+0xbd/0x1d0 fs/namei.c:3387
 do_sys_openat2+0x33c/0x4a0 fs/open.c:1179
 do_sys_open fs/open.c:1195 [inline]
 ksys_open include/linux/syscalls.h:1388 [inline]
 __do_sys_open fs/open.c:1201 [inline]
 __se_sys_open fs/open.c:1199 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1199
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18708 Comm: modprobe Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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