Re: 回复: [External] Re: [PATCH] nvme: fix heap-use-after-free and oops in bio_endio for nvme multipath

[Sagi Grimberg]

> 	No, I have not verified this issue with a system larger than 5.10.y(such as 5.15.y and 6.0 or furthor), because some function we need like cgroup in upper version kernel has changed too much, we can't use these upper version kernel.

Well, this would be the starting point.

> 	In addition , uptreams have change bi_disk's modify to bio_set_dev(bio, ns->disk->part0), and as you said there is no bi_disk in struct bio anymore. So that is too involving because of code dependencies,  i want to do is what you said, to send an alternative surgical fix.

The correct course of action would be to identify and narrow down the
fix for this upstream, and then backport it back to stable kernel 5.10.y

> 	(I will confirm upstream for this problem in the near future, if it have same problem, i will submit this fix.)

Great.

> 	I'm not sure what evidence is needed to prove this problem and patch. The following is child bio and parent bio struct when heap-use-after-free occur catched by crash(I turn on kasan and panic_on_warn).
>
> 	Please help me confirm if this is enough, thanks.

It is clear that there is a bug in 5.10.y, what we are discussing is:
1. Is this problem relevant to upstream kernel?
2. If yes, we can debate the correct fix, as your initial patch is not
   If not, then the upstream fix for this needs to be identified and
   backported.

Having stable kernels drift away from the original code-base is a bad
idea.