Re: [syzbot] [sctp?] [reiserfs?] KMSAN: uninit-value in __schedule (4)

[Alexander Potapenko]

On Thu, Sep 14, 2023 at 5:25 PM Marcelo Ricardo Leitner
<marcelo.leitner@xxxxxxxxx> wrote:
>
> On Tue, Sep 05, 2023 at 10:55:01AM -0700, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    a47fc304d2b6 Add linux-next specific files for 20230831
> > git tree:       linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=131da298680000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=6ecd2a74f20953b9
> > dashboard link: https://syzkaller.appspot.com/bug?extid=00f1a932d27258b183e7
> > compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=116e5fcba80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=118e912fa80000
>
> Not sure why sctp got tagged here. I could not find anything network
> related on this reproducer or console output.

I am afraid this is the effect of reports from different tools being
clustered together: https://github.com/google/syzkaller/issues/4168
The relevant KMSAN report can be viewed on the dashboard:
https://syzkaller.appspot.com/text?tag=CrashReport&x=144ba287a80000 -
that's where sctp was deduced from.

I suspect there's still nothing specific to sctp though: looks like
schedule_debug() somehow accidentally reads past the end of the task
stack.

>   Marcelo
>
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-- 
Alexander Potapenko
Software Engineer

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