Re: [syzbot] [io-uring?] KMSAN: uninit-value in io_rw_fail (2)

From: Jens Axboe
Date: Fri Feb 09 2024 - 17:14:27 EST


On 2/9/24 3:10 PM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 9f8413c4a66f Merge tag 'cgroup-for-6.8' of git://git.kerne..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1743d3e4180000
> kernel config: https://syzkaller.appspot.com/x/.config?x=656820e61b758b15
> dashboard link: https://syzkaller.appspot.com/bug?extid=0198afa90d8c29ef9557
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

This was fixed a while back, not sure why an old kernel is being tested. But
in any case, the result of this was just garbage in cqe->res for a request
that was prematurely errored. Nothing to worry about. In any case:

#syz fix: io_uring/rw: ensure io->bytes_done is always initialized

--
Jens Axboe