syzbot

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BUG: KCSAN: data-race in generic_permission / setattr_copy

write to 0xffff88816dacd7f8 of 2 bytes by task 6916 on cpu 1:
 setattr_copy+0x29d/0x2b0 fs/attr.c:321
 ext4_setattr+0x3d4/0xea0 fs/ext4/inode.c:5495
 notify_change+0x866/0x8e0 fs/attr.c:499
 chmod_common+0x13c/0x270 fs/open.c:648
 vfs_fchmod fs/open.c:664 [inline]
 __do_sys_fchmod fs/open.c:673 [inline]
 __se_sys_fchmod fs/open.c:667 [inline]
 __x64_sys_fchmod+0xb2/0x100 fs/open.c:667
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88816dacd7f8 of 2 bytes by task 6924 on cpu 0:
 acl_permission_check fs/namei.c:342 [inline]
 generic_permission+0x28/0x380 fs/namei.c:408
 do_inode_permission fs/namei.c:469 [inline]
 inode_permission+0x77/0x300 fs/namei.c:529
 vfs_tmpfile+0x69/0x320 fs/namei.c:3681
 do_tmpfile+0xa9/0x190 fs/namei.c:3755
 path_openat+0x1a02/0x1d30 fs/namei.c:3789
 do_filp_open+0xf6/0x200 fs/namei.c:3825
 do_sys_openat2+0xab/0x110 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_open fs/open.c:1427 [inline]
 __se_sys_open fs/open.c:1423 [inline]
 __x64_sys_open+0xe6/0x110 fs/open.c:1423
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x4000 -> 0x4504

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6924 Comm: syz-executor.2 Tainted: G        W          6.8.0-rc1-syzkaller-00311-g3a5879d495b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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