[moderation] [ext4?] KCSAN: data-race in fcntl_dirnotify / setattr_copy

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9bacdd8996c7 Merge tag 'for-6.7-rc1-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=166c7b98e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=a91f789b98394377
dashboard link: https://syzkaller.appspot.com/bug?extid=d13968d4234d750e213b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/be70757ec048/disk-9bacdd89.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/45e8c725b4dc/vmlinux-9bacdd89.xz
kernel image: https://storage.googleapis.com/syzbot-assets/82e551f976a9/bzImage-9bacdd89.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d13968...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in fcntl_dirnotify / setattr_copy

write to 0xffff888105d5f358 of 2 bytes by task 16878 on cpu 1:
setattr_copy+0x29d/0x2b0 fs/attr.c:321
ext4_setattr+0x3d4/0xea0 fs/ext4/inode.c:5488
notify_change+0x866/0x8e0 fs/attr.c:499
chmod_common+0x13c/0x270 fs/open.c:643
vfs_fchmod fs/open.c:659 [inline]
__do_sys_fchmod fs/open.c:668 [inline]
__se_sys_fchmod fs/open.c:662 [inline]
__x64_sys_fchmod+0xb2/0x100 fs/open.c:662
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888105d5f358 of 2 bytes by task 16872 on cpu 0:
fcntl_dirnotify+0xa9/0x540 fs/notify/dnotify/dnotify.c:290
do_fcntl+0x263/0xeb0 fs/fcntl.c:408
__do_sys_fcntl fs/fcntl.c:456 [inline]
__se_sys_fcntl+0xc4/0x180 fs/fcntl.c:441
__x64_sys_fcntl+0x43/0x50 fs/fcntl.c:441
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x41c0 -> 0x4000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16872 Comm: syz-executor.0 Not tainted 6.7.0-rc1-syzkaller-00012-g9bacdd8996c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.