[PATCH v2 2/3] nptl: Add libc allocated shadow stack for new threads

[Mark Brown]

On Wed, Oct 01, 2025 at 12:24:32PM -0400, enh wrote:

> is there a plan for sigaltstack() yet? as android's libc maintainer
> i'm particularly worried about that because android uses sigaltstack()
> by default for everyone, so any "ignore this special case" plan would
> be problematic for us.

> (whereas android's libc doesn't reuse thread stacks, so that's not a
> concern for us.)

I've not heard of one - we've talked around it a bunch but the
conclusion of the last discussion I remember was basically that nobody
involved at the time had a concrete use case for them so we felt we were
just talking endlessly around things without a clear idea of the
tradeoffs we might be making.  IIRC the concerns were about how to
represent switching to the alternate stack, especially when the switch
was due to the main stack being exhausted.
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