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BUG: KCSAN: data-race in d_shrink_add / walk_component

write to 0xffff8881252a3300 of 4 bytes by task 10034 on cpu 0:
 d_shrink_add+0xfa/0x140 fs/dcache.c:429
 __dput_to_list fs/dcache.c:874 [inline]
 __dput_to_list+0xda/0xf0 fs/dcache.c:864
 shrink_dentry_list+0x101/0x1c0 fs/dcache.c:1121
 shrink_dcache_sb+0x107/0x1d0 fs/dcache.c:1242
 reconfigure_super+0x31a/0x570 fs/super.c:940
 do_remount fs/namespace.c:2553 [inline]
 do_mount+0x1136/0x14f0 fs/namespace.c:3098
 __do_sys_mount fs/namespace.c:3316 [inline]
 __se_sys_mount fs/namespace.c:3293 [inline]
 __x64_sys_mount+0x12d/0x1a0 fs/namespace.c:3293
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881252a3300 of 4 bytes by task 10045 on cpu 1:
 d_is_symlink include/linux/dcache.h:419 [inline]
 step_into fs/namei.c:1878 [inline]
 walk_component+0xe9/0x9c0 fs/namei.c:1929
 link_path_walk.part.0+0x5ef/0xab0 fs/namei.c:2241
 link_path_walk fs/namei.c:2172 [inline]
 path_openat+0x150/0x3150 fs/namei.c:3606
 do_filp_open+0x11e/0x1b0 fs/namei.c:3637
 do_open_execat+0x111/0x3d0 fs/exec.c:860
 open_exec+0x50/0x80 fs/exec.c:892
 load_elf_binary+0x360/0x2d20 fs/binfmt_elf.c:761
 search_binary_handler fs/exec.c:1662 [inline]
 search_binary_handler+0x127/0x420 fs/exec.c:1639
 exec_binprm fs/exec.c:1705 [inline]
 __do_execve_file.isra.0+0xb53/0x1120 fs/exec.c:1825
 do_execveat_common fs/exec.c:1871 [inline]
 do_execve fs/exec.c:1888 [inline]
 __do_sys_execve fs/exec.c:1964 [inline]
 __se_sys_execve fs/exec.c:1959 [inline]
 __x64_sys_execve+0x62/0x80 fs/exec.c:1959
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10045 Comm: udevd Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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