From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
To: Jaromir Capik <jcapik@redhat.com>
Cc: 20614@debbugs.gnu.org, Andreas Schwab <schwab@suse.de>
Subject: bug#20614: Segmentation fault when building on Power8 Little Endian
Date: Sat, 10 Oct 2015 10:40:39 +0900 [thread overview]
Message-ID: <wltwpz8prc.wl%mituharu@math.s.chiba-u.ac.jp> (raw)
In-Reply-To: <1486765641.67448157.1444310865021.JavaMail.zimbra@redhat.com>
>>>>> On Thu, 8 Oct 2015 09:27:45 -0400 (EDT), Jaromir Capik <jcapik@redhat.com> said:
>> > By the way .toc is still not fixed. It is specific to ppc64. And it
>> > doesn't cause the segfault, though. It has a data and addresses.
>> > It seems that unexec corrupted it:(
>>
>> I guess you mean the entry in
>> https://bugzilla.redhat.com/show_bug.cgi?id=1265271#c16 .
>>
>> .rela.plt -> .plt
>> .rela.toc -> empty string
>>
>> What does the above notation stand for? Is this the output of some
>> tool? Then what would be the output for src/temacs?
> That is a debug output I put in the relocation udoing loop where
> the segfault occured when the section names were compared with listed
> literals.
> I was printing the section names of REL/RELA sections and their
> PROGBITS/NOBITS counterparts. The segfault occured when accessing
> 'old_section_names + NEW_SECTION_H (section.sh_info).sh_name' where
> section.sh_name was '.rela.toc'. That means it was pointing to
> an invalid address. When the .plt evaluation was fixed, the segfault
> disappeared, but the NEW_SECTION_H (section.sh_info).sh_type is NULL
> now and the section name is empty. The question is whether this is ok
> or not. After looking at the complete list of sections it seems to be
> a PPC specific oddity and I'm looking at the code to make myself sure
> it doesn't need a special care. So, right now it requires no attention
> from your side.
Well, according to the output of "readelf -S ./temacs" shown in
https://bugzilla.redhat.com/show_bug.cgi?id=1265271#c8 , the "Info"
column, which seems to correspond to the sh_info member, for the
.rela.toc section already points to the 0th (NULL) section even for
temacs. So I think it is OK for the dumped executable to have the
same value.
Andreas, do you know if the change I proposed in
http://lists.gnu.org/archive/html/bug-gnu-emacs/2015-10/msg00382.html
does not break your fix for PowerPC64 in 2005 below?
http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=825dad898e2d43eb2802c070fd4ce08816f907df
Do you happen to have the output of "readelf -S temacs" or something
like that as of your fix?
YAMAMOTO Mitsuharu
mituharu@math.s.chiba-u.ac.jp
next prev parent reply other threads:[~2015-10-10 1:40 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-20 7:56 bug#20614: Segmentation fault when building on Power8 Little Endian Petr Hracek
2015-05-20 14:45 ` Eli Zaretskii
2015-05-20 16:12 ` Glenn Morris
2015-05-21 12:55 ` Petr Hracek
2015-07-13 11:27 ` Petr Hracek
2015-07-13 13:16 ` Andreas Schwab
2015-07-14 7:52 ` Petr Hracek
2015-07-14 8:14 ` Andreas Schwab
2015-09-16 11:28 ` Petr Hracek
2015-09-22 10:17 ` Petr Hracek
2015-09-23 8:06 ` Petr Hracek
2015-09-23 9:34 ` Eli Zaretskii
2015-09-23 11:00 ` Petr Hracek
2015-09-23 11:14 ` Eli Zaretskii
2015-09-23 12:11 ` Petr Hracek
2015-09-23 12:23 ` Eli Zaretskii
2015-09-24 11:04 ` Petr Hracek
2015-09-24 15:32 ` Eli Zaretskii
2015-09-24 17:56 ` Petr Hracek
2015-09-26 7:58 ` Eli Zaretskii
2015-09-30 10:39 ` Petr Hracek
2015-10-01 7:43 ` Eli Zaretskii
2015-10-01 8:46 ` Petr Hracek
2015-10-01 11:44 ` Petr Hracek
2015-10-01 11:53 ` Petr Hracek
2015-10-01 12:22 ` Eli Zaretskii
2015-10-01 14:05 ` Petr Hracek
2015-10-01 16:01 ` Eli Zaretskii
2015-10-02 8:36 ` Petr Hracek
2015-10-02 8:49 ` Eli Zaretskii
2015-10-02 12:58 ` Petr Hracek
2015-10-02 13:46 ` Eli Zaretskii
2015-10-05 7:40 ` Petr Hracek
2015-10-05 8:27 ` Eli Zaretskii
2015-10-05 9:16 ` Petr Hracek
2015-10-05 9:39 ` Eli Zaretskii
2015-10-05 11:23 ` Petr Hracek
2015-10-05 11:40 ` Eli Zaretskii
2015-10-05 14:07 ` Petr Hracek
2015-10-05 16:52 ` Eli Zaretskii
2015-10-06 8:41 ` Petr Hracek
2015-10-06 11:52 ` Petr Hracek
2015-10-06 14:55 ` Eli Zaretskii
2015-10-07 8:17 ` Petr Hracek
2015-10-07 10:56 ` YAMAMOTO Mitsuharu
2015-10-07 12:26 ` Petr Hracek
2015-10-08 0:54 ` YAMAMOTO Mitsuharu
2015-10-08 13:27 ` Jaromir Capik
2015-10-10 1:40 ` YAMAMOTO Mitsuharu [this message]
2015-10-10 15:44 ` Andreas Schwab
2015-10-13 7:30 ` Petr Hracek
2015-10-13 8:30 ` Andreas Schwab
2015-10-16 15:24 ` Jaromir Capik
2015-10-19 7:20 ` Andreas Schwab
2015-09-23 12:10 ` Petr Hracek
2015-09-23 12:21 ` Eli Zaretskii
2015-09-23 13:10 ` Petr Hracek
2015-09-23 13:38 ` Petr Hracek
2015-09-23 13:57 ` Eli Zaretskii
2015-09-23 17:25 ` Glenn Morris
2015-09-23 17:47 ` Glenn Morris
2015-09-29 8:15 ` Florian Weimer
2015-07-13 12:17 ` bug#20614: Segmentation fault when building on Power8 Little Endian (ppc64le) Petr Hracek
2015-11-17 1:59 ` bug#20614: alignment problem with recent Emacs unexelf.c changes Paul Eggert
2015-11-17 9:03 ` Alan Modra
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