Messages in this thread | | | Date | Thu, 28 May 2015 12:51:31 +0100 | From | "Jan Beulich" <> | Subject | Re: [PATCH] x86/debug: Remove perpetually broken, unmaintainable dwarf annotations |
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>>> On 28.05.15 at 13:20, <mingo@kernel.org> wrote: > * Jan Beulich <JBeulich@suse.com> wrote: >> Not sure why assembly code should look like C code. It's a matter of taste >> perhaps, and I can see your point, but I'm also not really eager to do > changes >> just to match other people's taste. And just like above - certainly not >> something for this patch I would think. > > Yeah, no, so this isn't going to work that way. > > On one hand you want dwarf annotations mostly for the out of tree > dwarf-unwinding > stack backtraces patch on SUSE kernels, while for the upstream kernel it's > mostly > just unreadable gunk in some of the most security sensitive code paths of > the > kernel, which only gets in the way of readability. > > But on the other hand you are unwilling to (or don't have the time to) do a > proper > job of making this palatable for upstream. > > That's unacceptable from the upstream kernel's POV, so instead of limping > forward > I'll do the attached patch: it gets rid of the unmaintainable dwarf mess > from low > level x86 assembly code. This isn't a new concern, a couple of years ago we > almost > did this.
I can understand your motivation, yet I still view it as rather sad that you move this way. Indeed I don't have the time to do major rework in this area, but I don't think you can blame me for not having tried to at least investigate and eliminate breakage when I found such (which, as you say, happens every now and then). Yet I do recall people indicating that the unwind data can be useful for other than the out-of-tree live stack unwinder. I.e. those will be broken along with that code which we're _forced_ to maintain out-of-tree.
> and meanwhile you can keep a revert of this patch ported to SUSE kernels in > whatever fashion you prefer.
Funny suggestion - I don't think that's reasonable for us to do. Or if we were to, we could as well invest in doing the re-work you're asking for; I don't think anyone will have the time to do either.
Jan
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