KCSAN: data-race in do_iter_write / setattr

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_iter_write / setattr_copy ext4				1	933d	933d	0/26	auto-closed as invalid on 2021/11/12 05:10

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BUG: KCSAN: data-race in do_iter_write / setattr_copy

write to 0xffff88810ad6b328 of 2 bytes by task 31819 on cpu 0:
 setattr_copy+0x355/0x370 fs/attr.c:320
 ext4_setattr+0x52a/0xf10 fs/ext4/inode.c:5633
 notify_change+0xa5c/0xad0 fs/attr.c:482
 chmod_common+0x12c/0x260 fs/open.c:606
 do_fchmodat fs/open.c:645 [inline]
 __do_sys_fchmodat fs/open.c:658 [inline]
 __se_sys_fchmodat fs/open.c:655 [inline]
 __x64_sys_fchmodat+0x9d/0x110 fs/open.c:655
 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+0x63/0xcd

read to 0xffff88810ad6b328 of 2 bytes by task 31810 on cpu 1:
 fsnotify_parent include/linux/fsnotify.h:65 [inline]
 fsnotify_file include/linux/fsnotify.h:99 [inline]
 fsnotify_modify include/linux/fsnotify.h:317 [inline]
 do_iter_write+0x563/0x750 fs/read_write.c:865
 vfs_iter_write+0x4c/0x70 fs/read_write.c:902
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:931
 splice_direct_to_actor+0x305/0x620 fs/splice.c:886
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
 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+0x63/0xcd

value changed: 0x8000 -> 0x86ee

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31810 Comm: syz-executor.4 Tainted: G        W          6.2.0-rc5-syzkaller-00020-g7bf70dbb1882-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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