Subject: Re: [PATCH net v2] ipv6: anycast: insert aca into global hash under idev->lock

From: Jiayuan Chen <[email-masked]>
Date: Sat, 30 May 2026 13:00:13 +0800

On 5/30/26 4:51 AM, Jakub Kicinski wrote:
> On Fri, 29 May 2026 23:22:18 +0800 Jiayuan Chen wrote:
>> syzbot reported a splat [1]: a slab-use-after-free in
>> ipv6_chk_acast_addr(), which walks the global inet6_acaddr_lst[] hash
>> under RCU and dereferences a struct ifacaddr6 that has already been
>> freed while still linked in the hash, so a later reader walks into a
>> dangling node.
> Please do not violate the 24h repost grace period on netdev.
> We are tracking the violations now, if you keep doing this
> there will be consequences..

Oops, sorry about that. I slept on it and somehow got confused about the 
timing.

I will make sure to wait for the full 24 hours next time.