[moderation] [pci?] KCSAN: data-race in vga_arb_write / vga_arb_write (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 296455ade1fd Merge tag 'char-misc-6.8-rc1' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1506130be80000
kernel config: https://syzkaller.appspot.com/x/.config?x=1a15191e1424b0dc
dashboard link: https://syzkaller.appspot.com/bug?extid=6a1aea810a45c686a583
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bhel...@google.com linux-...@vger.kernel.org linu...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/691ac77cade8/disk-296455ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e2cd631ad41b/vmlinux-296455ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e731931a6edb/bzImage-296455ad.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6a1aea...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in vga_arb_write / vga_arb_write

read to 0xffff88813acfac20 of 4 bytes by task 4261 on cpu 1:
vga_arb_write+0xf06/0x1410 drivers/pci/vgaarb.c:1255
vfs_write+0x27a/0x790 fs/read_write.c:588
ksys_write+0xeb/0x1a0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:652
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-write to 0xffff88813acfac20 of 4 bytes by task 4257 on cpu 0:
vga_arb_write+0x1216/0x1410 drivers/pci/vgaarb.c:1206
vfs_write+0x27a/0x790 fs/read_write.c:588
ksys_write+0xeb/0x1a0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:652
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: 0x0000001a -> 0x00000003

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4257 Comm: syz-executor.5 Not tainted 6.7.0-syzkaller-11091-g296455ade1fd #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.