Re: [PATCH] rseq/selftests: ensure the rseq abi TLS is actually 1024 bytes

[Mark Brown]

On Tue, Mar 18, 2025 at 10:50:58AM -0400, Michael Jeanson wrote:
> On 2025-03-18 10:01, Mark Brown wrote:
> > On Tue, Mar 11, 2025 at 03:21:45PM -0400, Michael Jeanson wrote:
> > 
> > > Adding the aligned(1024) attribute to the definition of __rseq_abi did
> > > not increase its size to 1024, for this attribute to impact the size of
> > > __rseq_abi it would need to be added to the declaration of 'struct
> > > rseq_abi'. We only want to increase the size of the TLS allocation to
> > > ensure registration will succeed with future extended ABI. Use a union
> > > with a dummy member to ensure we allocate 1024 bytes.

> > This is in today's -next and breaks the build of the KVM selftests:

...

> > since unlike the rseq tests the KVM rseq test includes the UAPI header
> > for rseq which the padded union conflicts with.

> Oh, I missed that, we need a more unique name for the union.

> I'm unfamiliar with the workflow of linux-next, should I send a V2 of the
> current patch, or a new one that applies on top?

It depends on the tree that the patch was applied to - -next merges the
current stat of the maintainer trees daily rather than applying anything
itself.  In this case that's -tip, I think incremental is good for them
but ICBW?

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