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bug#20614: Segmentation fault when building on Power8 Little Endian
From: |
YAMAMOTO Mitsuharu |
Subject: |
bug#20614: Segmentation fault when building on Power8 Little Endian |
Date: |
Sat, 10 Oct 2015 10:40:39 +0900 |
User-agent: |
Wanderlust/2.14.0 (Africa) SEMI/1.14.6 (Maruoka) FLIM/1.14.8 (Shijō) APEL/10.6 Emacs/22.3 (sparc-sun-solaris2.8) MULE/5.0 (SAKAKI) |
>>>>> 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
- bug#20614: Segmentation fault when building on Power8 Little Endian, (continued)
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Eli Zaretskii, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Eli Zaretskii, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, YAMAMOTO Mitsuharu, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, YAMAMOTO Mitsuharu, 2015/10/08
- bug#20614: Segmentation fault when building on Power8 Little Endian, Jaromir Capik, 2015/10/09
- bug#20614: Segmentation fault when building on Power8 Little Endian,
YAMAMOTO Mitsuharu <=
- bug#20614: Segmentation fault when building on Power8 Little Endian, Andreas Schwab, 2015/10/10
- bug#20614: Segmentation fault when building on Power8 Little Endian, Petr Hracek, 2015/10/13
- bug#20614: Segmentation fault when building on Power8 Little Endian, Andreas Schwab, 2015/10/13
- bug#20614: Segmentation fault when building on Power8 Little Endian, Jaromir Capik, 2015/10/16
- bug#20614: Segmentation fault when building on Power8 Little Endian, Andreas Schwab, 2015/10/19
bug#20614: Segmentation fault when building on Power8 Little Endian, Florian Weimer, 2015/10/08