Subject: Re: bug#25241: Emacs 25.1.90 pretest crash on macOS 10.10 Yosemite

From: Alexis Layton <[email-masked]>
Date: Wed, 21 Dec 2016 15:27:30 -0500

> On 2016–12–20, at 22:34, Eli Zaretskii <[email-masked]> wrote:
> 
>> From: Alexis Layton <[email-masked]>
>> Date: Tue, 20 Dec 2016 21:45:47 -0500
>> 
>> I run the Mac OS (X) binary distributions built by David Caldwell at www.emacsformacosx.com, which claim to be pure GNU Emacs. The latest pretest 25.1.90 immediately crashes on OS X 10.10.5 Yosemite.
>> 
>> $ emacs -nw -q
>> Illegal instruction: 4
>> 
>> I can't really give much more information. 25.1 and all of its protests and release candidates ran fine, and the released version continues to do so.
> 
> It would help if you could run Emacs under a debugger and show
> backtrace when it crashes.
> 
> Thanks.

Sadly this is not as informative as it looks:

$ lldb /Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9 
(lldb) target create "/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9"
Current executable set to '/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9' (x86_64).
(lldb) r
Process 23181 launched: '/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9' (x86_64)
Process 23181 stopped
* thread #1: tid = 0x1550e6, 0x000000010084979d libnettle.6.dylib`nettle_sha256_init + 4, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #0: 0x000000010084979d libnettle.6.dylib`nettle_sha256_init + 4
libnettle.6.dylib`nettle_sha256_init:
->  0x10084979d <+4>:  vmovaps 0x130bb(%rip), %xmm0      ; nettle_sha256_init.H0 + 16
    0x1008497a5 <+12>: vmovups %xmm0, 0x10(%rdi)
    0x1008497aa <+17>: vmovaps 0x1309e(%rip), %xmm0      ; nettle_sha256_init.H0
    0x1008497b2 <+25>: vmovups %xmm0, (%rdi)