syzbot

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BUG: KCSAN: data-race in do_dentry_open / setattr_copy

write to 0xffff88811c409d48 of 2 bytes by task 12706 on cpu 0:
 setattr_copy+0x238/0x250 fs/attr.c:261
 shmem_setattr+0xb0/0x410 mm/shmem.c:1118
 notify_change+0x8e6/0xa00 fs/attr.c:424
 chmod_common+0x13c/0x270 fs/open.c:606
 do_fchmodat fs/open.c:645 [inline]
 __do_sys_chmod fs/open.c:663 [inline]
 __se_sys_chmod fs/open.c:661 [inline]
 __x64_sys_chmod+0x8f/0x100 fs/open.c:661
 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 0xffff88811c409d48 of 2 bytes by task 1843 on cpu 1:
 do_dentry_open+0x161/0x850 fs/open.c:813
 vfs_open+0x43/0x50 fs/open.c:981
 do_open fs/namei.c:3520 [inline]
 path_openat+0x16cf/0x1b30 fs/namei.c:3653
 do_filp_open+0x105/0x220 fs/namei.c:3680
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1278
 do_sys_open fs/open.c:1294 [inline]
 __do_sys_openat fs/open.c:1310 [inline]
 __se_sys_openat fs/open.c:1305 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1305
 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: 0x6180 -> 0x61b0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1843 Comm: syz-executor.3 Not tainted 5.19.0-rc3-syzkaller-00146-g92f20ff72066-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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