KCSAN: data-race in dnotify_flush / setattr

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in dnotify_flush / setattr_copy fs				1	1378d	1378d	0/26	auto-closed as invalid on 2020/08/22 18:57

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BUG: KCSAN: data-race in dnotify_flush / setattr_copy

write to 0xffff88810699b080 of 2 bytes by task 20666 on cpu 0:
 setattr_copy+0x1af/0x1c0 fs/attr.c:247
 simple_setattr+0x95/0xb0 fs/libfs.c:509
 sockfs_setattr+0x23/0xc0 net/socket.c:593
 notify_change+0x8a3/0xa80 fs/attr.c:398
 chmod_common+0x11c/0x250 fs/open.c:585
 vfs_fchmod fs/open.c:601 [inline]
 __do_sys_fchmod fs/open.c:610 [inline]
 __se_sys_fchmod fs/open.c:604 [inline]
 __x64_sys_fchmod+0xac/0xf0 fs/open.c:604
 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 0xffff88810699b080 of 2 bytes by task 20668 on cpu 1:
 dnotify_flush+0x2e/0x300 fs/notify/dnotify/dnotify.c:145
 filp_close+0xa9/0xf0 fs/open.c:1315
 close_fd+0x1b1/0x1e0 fs/file.c:628
 __do_sys_close fs/open.c:1331 [inline]
 __se_sys_close fs/open.c:1329 [inline]
 __x64_sys_close+0x1b/0x70 fs/open.c:1329
 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: 0xc1ff -> 0xc001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20668 Comm: syz-executor.5 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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