[moderation] [ext4?] KCSAN: data-race in generic_permission / setattr_copy (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3a5879d495b2 Merge tag 'ata-6.8-rc2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15078ea0180000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bd33f45956bbc2
dashboard link: https://syzkaller.appspot.com/bug?extid=d6873b7d6e1a55bec546
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/a96be9241f44/disk-3a5879d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/386c65ac5e13/vmlinux-3a5879d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0edb10e21dd1/bzImage-3a5879d4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d6873b...@syzkaller.appspotmail.com

==================================================================
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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[syzbot]

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