Re: [PATCH] usercopy: delete __noreturn from usercopy_abort

[Kees Cook]

On Mon, Mar 04, 2024 at 04:15:07PM +0100, Jann Horn wrote:
> On Mon, Mar 4, 2024 at 3:02 AM Jiangfeng Xiao <xiaojiangfeng@xxxxxxxxxx> wrote:
> > When the last instruction of a noreturn function is a call
> > to another function, the return address falls outside
> > of the function boundary. This seems to cause kernel
> > to interrupt the backtrace.

FWIW, all email from huawei.com continues to get eaten by anti-spam
checking. I've reported this a few times -- it'd be really nice if the
domain configuration could get fixed.

> [...]
> > Delete __noreturn from usercopy_abort,
> 
> This sounds like the actual bug is in the backtracing logic? I don't
> think removing __noreturn annotations from an individual function is a
> good fix, since the same thing can happen with other __noreturn
> functions depending on what choices the compiler makes.

Yeah, NAK. usercopy_abort() doesn't return. It ends with BUG().

-- 
Kees Cook