Re: [syzbot] KASAN: vmalloc-out-of-bounds Write in ringbuf_map_alloc

[Daniel Borkmann]

On 2/2/22 3:49 PM, Marco Elver wrote:
> On Wed, 2 Feb 2022 at 15:36, syzbot
> <syzbot+5ad567a418794b9b5983@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > syzbot has bisected this issue to:
> >
> > commit c34cdf846c1298de1c0f7fbe04820fe96c45068c
> > Author: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> > Date:   Wed Feb 2 01:04:27 2022 +0000
> >
> >      kasan, vmalloc: unpoison VM_ALLOC pages after mapping
>
> Is this a case of a new bug surfacing due to KASAN improvements? But
> it's not quite clear to me why this commit.
>
> Andrey, any thoughts?

Marco / Andrey, fix should be this one:

https://patchwork.kernel.org/project/netdevbpf/patch/20220202060158.6260-1-houtao1@xxxxxxxxxx/

> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=128cb900700000
> > start commit:   6abab1b81b65 Add linux-next specific files for 20220202
> > git tree:       linux-next
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=118cb900700000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=168cb900700000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=b8d8750556896349
> > dashboard link: https://syzkaller.appspot.com/bug?extid=5ad567a418794b9b5983
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1450d9f0700000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=130ef35bb00000
> >
> > Reported-by: syzbot+5ad567a418794b9b5983@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: c34cdf846c12 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection