syzbot

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BUG: KCSAN: data-race in ext4_setattr / generic_permission

write to 0xffff888106fb2184 of 4 bytes by task 14358 on cpu 1:
 ext4_setattr+0x51b/0xec0 fs/ext4/inode.c:5383
 notify_change+0x8a3/0xa80 fs/attr.c:398
 chown_common+0x23e/0x370 fs/open.c:682
 do_fchownat+0xf4/0x190 fs/open.c:713
 __do_sys_lchown fs/open.c:738 [inline]
 __se_sys_lchown fs/open.c:736 [inline]
 __x64_sys_lchown+0x46/0x50 fs/open.c:736
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106fb2184 of 4 bytes by task 14359 on cpu 0:
 i_uid_into_mnt include/linux/fs.h:1619 [inline]
 acl_permission_check fs/namei.c:330 [inline]
 generic_permission+0x32/0x420 fs/namei.c:392
 do_inode_permission fs/namei.c:453 [inline]
 inode_permission+0x6b/0x290 fs/namei.c:513
 may_lookup fs/namei.c:1672 [inline]
 link_path_walk+0x17d/0x770 fs/namei.c:2228
 path_lookupat+0x8b/0x3d0 fs/namei.c:2437
 filename_lookup+0x118/0x3b0 fs/namei.c:2467
 user_path_at_empty+0x3b/0x50 fs/namei.c:2747
 user_path_at include/linux/namei.h:57 [inline]
 path_setxattr+0x4b/0x180 fs/xattr.c:590
 __do_sys_setxattr fs/xattr.c:611 [inline]
 __se_sys_setxattr fs/xattr.c:607 [inline]
 __x64_sys_setxattr+0x69/0x80 fs/xattr.c:607
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000041ed -> 0x00004028

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14359 Comm: syz-executor.3 Tainted: G        W         5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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