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Re: [RFC PATCH 0/5] arm64: Signal context expansion
- From: Florian Weimer <fweimer at redhat dot com>
- To: Dave Martin <Dave dot Martin at arm dot com>, linux-arm-kernel at lists dot infradead dot org, libc-alpha at sourceware dot org
- Cc: Ard Biesheuvel <ard dot biesheuvel at linaro dot org>
- Date: Fri, 9 Sep 2016 16:39:14 +0200
- Subject: Re: [RFC PATCH 0/5] arm64: Signal context expansion
- Authentication-results: sourceware.org; auth=none
- References: <1473430576-20792-1-git-send-email-Dave.Martin@arm.com>
On 09/09/2016 04:15 PM, Dave Martin wrote:
This new record can be added in sigframe.__reserved[] if there is a
need to allocate extra space beyond the standard signal frame. The
extra block of memory referenced by extra_context can then be parsed in
the same way as sigcontext.__reserved[]. Old code should just ignore
the whole thing as an unrecognised record. To maintain backward
compatibility, signal context records defined today are always placed
directly in __reserved[], never in the block referenced by
extra_context.
Do you add this extra information only if the stack is sufficiently large?
x86_64 adds the new information even for small stacks set up with
sigaltstack, leading to memory corruption on bleeding-edge hardware:
<https://bugzilla.kernel.org/show_bug.cgi?id=153531>
Thanks,
Florian