From: "Jan Djärv" <jan.h.d@swipnet.se>
To: David Caldwell <david@porkrind.org>
Cc: 18505@debbugs.gnu.org
Subject: bug#18505: 24.3.93; intermittent unexec failures when building on Mac OS X 10.10 beta, Xcode 6.0
Date: Sun, 21 Sep 2014 11:15:26 +0200 [thread overview]
Message-ID: <927680BE-0933-4F3E-AAAA-F2F3745F7D55@swipnet.se> (raw)
In-Reply-To: <541DC7EE.6080309@porkrind.org>
Hello.
20 sep 2014 kl. 20:31 skrev David Caldwell <david@porkrind.org>:
> On 9/20/14 8:31 AM, Jan Djärv wrote:
>> Hello.
>>
>> 19 sep 2014 kl. 06:13 skrev David Caldwell <david@porkrind.org>:
>>
>>> Hello,
>>>
>>> I tried to build the latest pretest on Mac OS X Yosemite Beta with the
>>> new Xcode 6.0 (GM) tools and ran into this error during the unexec step:
>>>
>>> unexec: not enough room for load commands for new __DATA segments
>>
>> Does it happen all the time or just some times?
>
> It depends on 2 variables: the number of load commands that need to be
> added (num_unexec_regions) and text_seg_lowest_offset.
>
> num_unexec_regions jumps around a lot, doing "make clean && make" over
> and over it'll be different every time. Somewhere between 12 and 34.
What makes it do that? Some address randomization? Some other unknown bug?
I would expect num_unexec_regions to be the same for every make. text_seg_lowest_offset could be address randomization, but if it stays somewhat constant, that can't be it.
I've seen this failure before, but usually a new make works.
I'm trying to decide if this is emacs 24 or trunk material.
Is there a way to dynamically react to these changes and adjust headerpad_extra dynamically at dump time?
>
> text_seg_lowest_offset seems more stable, but it still changes. When I
> first unpacked the tarball and compiled, text_seg_lowest_offset was very
> low: 0x17c0. This stayed constant for about an hour while I was
> debugging this (adding debug prints) and then mysteriously jumped up to
> 0x24f0 at which point the unexec started succeeding without the change
> to headerpad_extra.
>
> I just unpacked a clean pretest source directory and
> text_seg_lowest_offset was 0x17a0 and unexec failed.
>
> Doing
> (make clean && make) 2>&1 | grep "Lowest offset of all sections"
> over and over gives me:
>
> Lowest offset of all sections in __TEXT segment: 0x17a0
> Lowest offset of all sections in __TEXT segment: 0x17a0
> Lowest offset of all sections in __TEXT segment: 0x17a0
> Lowest offset of all sections in __TEXT segment: 0x17a0
> Lowest offset of all sections in __TEXT segment: 0x17a0
> Lowest offset of all sections in __TEXT segment: 0x17a0
>
> Though one of those times it didn't fail (presumably because
> num_unexec_regions was low enough).
Jan D.
next prev parent reply other threads:[~2014-09-21 9:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-19 4:13 bug#18505: 24.3.93; intermittent unexec failures when building on Mac OS X 10.10 beta, Xcode 6.0 David Caldwell
2014-09-20 15:31 ` Jan Djärv
2014-09-20 18:31 ` David Caldwell
2014-09-21 9:15 ` Jan Djärv [this message]
2014-09-21 18:07 ` David Caldwell
2014-09-21 20:37 ` Jan Djärv
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