syzbot

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BUG: KCSAN: data-race in generic_fillattr / shmem_mknod

read-write to 0xffff888103ad8448 of 8 bytes by task 3356 on cpu 1:
 shmem_mknod+0xd1/0x160 mm/shmem.c:2823
 shmem_create+0x2f/0x40 mm/shmem.c:2874
 lookup_open fs/namei.c:3331 [inline]
 open_last_lookups fs/namei.c:3401 [inline]
 path_openat+0xc50/0x1b30 fs/namei.c:3607
 do_filp_open+0x105/0x220 fs/namei.c:3637
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1254
 do_sys_open fs/open.c:1270 [inline]
 __do_sys_openat fs/open.c:1286 [inline]
 __se_sys_openat fs/open.c:1281 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1281
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff888103ad8448 of 8 bytes by task 2144 on cpu 0:
 i_size_read include/linux/fs.h:849 [inline]
 generic_fillattr+0x203/0x2b0 fs/stat.c:53
 shmem_getattr+0x22c/0x2c0 mm/shmem.c:1061
 vfs_getattr_nosec fs/stat.c:123 [inline]
 vfs_getattr fs/stat.c:160 [inline]
 vfs_statx+0x26e/0x3d0 fs/stat.c:232
 vfs_fstatat fs/stat.c:255 [inline]
 __do_sys_newfstatat fs/stat.c:425 [inline]
 __se_sys_newfstatat+0x8a/0x290 fs/stat.c:419
 __x64_sys_newfstatat+0x51/0x60 fs/stat.c:419
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x0000000000001770 -> 0x0000000000001784

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2144 Comm: udevd Not tainted 5.18.0-syzkaller-10037-g7e284070abe5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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