Subject: Re: [syzbot] [wireguard?] KASAN: slab-use-after-free Write in enqueue_timer

From: Jakub Kicinski <[email-masked]>
Date: Wed, 24 May 2023 08:39:35 -0700

On Wed, 24 May 2023 08:33:41 -0700 Jakub Kicinski wrote:
> On Wed, 24 May 2023 10:24:31 +0200 Dmitry Vyukov wrote:
> > FWIW There are more report examples on the dashboard.
> > There are some that don't mention wireguard nor usbnet, e.g.:
> > https://syzkaller.appspot.com/text?tag=CrashReport&x=17dd2446280000
> > So that's probably red herring. But they all seem to mention alloc_netdev_mqs.  
> 
> While we have you, let me ask about the possibility of having vmcore
> access - I think it'd be very useful to solve this mystery. 
> With a bit of luck the timer still has the function set.

I take that back.

Memory state around the buggy address:
 ffff88801ecc1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801ecc1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801ecc1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb  
                   ^
 ffff88801ecc1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801ecc1600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb