syzbot

==================================================================
BUG: KCSAN: data-race in drop_nlink / generic_fillattr

write to 0xffff888108792968 of 4 bytes by task 17432 on cpu 1:
 drop_nlink+0x37/0x90 fs/inode.c:305
 shmem_unlink+0x162/0x180 mm/shmem.c:3028
 shmem_rename2+0x2f5/0x420 mm/shmem.c:3120
 vfs_rename+0x8ef/0xe20 fs/namei.c:4312
 do_renameat2+0x5c3/0x900 fs/namei.c:4457
 __do_sys_rename fs/namei.c:4508 [inline]
 __se_sys_rename fs/namei.c:4506 [inline]
 __x64_sys_rename+0x58/0x60 fs/namei.c:4506
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888108792968 of 4 bytes by task 4897 on cpu 0:
 generic_fillattr+0x74/0x180 fs/stat.c:41
 shmem_getattr+0x227/0x2c0 mm/shmem.c:1075
 vfs_getattr_nosec fs/stat.c:87 [inline]
 vfs_getattr fs/stat.c:124 [inline]
 vfs_fstat+0x1c9/0x390 fs/stat.c:146
 __do_sys_newfstat fs/stat.c:386 [inline]
 __se_sys_newfstat+0x35/0x240 fs/stat.c:383
 __x64_sys_newfstat+0x2d/0x40 fs/stat.c:383
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4897 Comm: systemd-udevd Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================