syzbot

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BUG: KCSAN: data-race in shmem_reserve_inode / shmem_statfs

write to 0xffff888105f4a038 of 8 bytes by task 15267 on cpu 0:
 shmem_reserve_inode+0xb5/0x320 mm/shmem.c:287
 shmem_get_inode+0x56/0x440 mm/shmem.c:2302
 shmem_mknod+0x3b/0x170 mm/shmem.c:2862
 shmem_create+0x2f/0x40 mm/shmem.c:2925
 lookup_open fs/namei.c:3221 [inline]
 open_last_lookups fs/namei.c:3291 [inline]
 path_openat+0xd36/0x21b0 fs/namei.c:3497
 do_filp_open+0xd9/0x1f0 fs/namei.c:3527
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105f4a038 of 8 bytes by task 4828 on cpu 1:
 shmem_statfs+0x10b/0x130 mm/shmem.c:2846
 statfs_by_dentry fs/statfs.c:66 [inline]
 vfs_statfs+0xb7/0x1c0 fs/statfs.c:90
 fd_statfs fs/statfs.c:120 [inline]
 __do_sys_fstatfs fs/statfs.c:216 [inline]
 __se_sys_fstatfs fs/statfs.c:213 [inline]
 __x64_sys_fstatfs+0x6c/0x130 fs/statfs.c:213
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4828 Comm: systemd-journal Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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