Re: [PATCH 0/9 v6] bfq: Avoid use-after-free when moving processes between cgroups

yukuai (C)
2022-04-01T03:40:46Z

在 2022/03/30 20:42, Jan Kara 写道:
> Hello,
>
> with a big delay (I'm sorry for that) here is the sixth version of my patches
> to fix use-after-free issues in BFQ when processes with merged queues get moved
> to different cgroups. The patches have survived some beating in my test VM, but
> so far I fail to reproduce the original KASAN reports so testing from people
> who can reproduce them is most welcome. Kuai, can you please give these patches
> a run in your setup? Thanks a lot for your help with fixing this!
>
Hi, Jan

I ran the reproducer for more than 12 hours aready, and the uaf is not
reporduced anymore. Before this patchset this problem can be reporduced
within an hour.

Thanks,
Kuai
> Changes since v5:
> * Added handling of situation when bio is submitted for a cgroup that has
> already went through bfq_pd_offline()
> * Convert bfq to avoid using deprecated __bio_blkcg() and thus fix possible
> races when returned cgroup can change while bfq is working with a request
>
> Changes since v4:
> * Even more aggressive splitting of merged bfq queues to avoid problems with
> long merge chains.
>
> Changes since v3:
> * Changed handling of bfq group move to handle the case when target of the
> merge has moved.
>
> Changes since v2:
> * Improved handling of bfq queue splitting on move between cgroups
> * Removed broken change to bfq_put_cooperator()
>
> Changes since v1:
> * Added fix for bfq_put_cooperator()
> * Added fix to handle move between cgroups in bfq_merge_bio()
>
> Honza
> Previous versions:
> Link: http://lore.kernel.org/r/20211223171425.3551-1-jack@suse.cz # v1
> Link: http://lore.kernel.org/r/20220105143037.20542-1-jack@suse.cz # v2
> Link: http://lore.kernel.org/r/20220112113529.6355-1-jack@suse.cz # v3
> Link: http://lore.kernel.org/r/20220114164215.28972-1-jack@suse.cz # v4
> Link: http://lore.kernel.org/r/20220121105503.14069-1-jack@suse.cz # v5
> .
>