Your message dated Tue, 19 Jan 2016 14:07:16 +0100
with message-id <[email protected]>
and subject line Re: Bug#806667: emacs24: FTBFS on sparc64, Bus Error during
lucid build
has caused the Debian Bug report #806667,
regarding emacs24: FTBFS on sparc64, Bus Error during lucid build
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
806667: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=806667
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Source: emacs24
Severity: normal
Tags: upstream patch
User: [email protected]
Usertags: sparc64
Dear Maintainer,
The emacs24 build is currently failing on sparc64 with a Bus
Error. You can see an example build log here:
https://buildd.debian.org/status/fetch.php?pkg=emacs24&arch=sparc64&ver=24.5%2B1-5&stamp=1448688813
I've attached a patch that corrects an unaligned pointer dereference
in src/unexelf.c. But my fix is more of a hack and probably not suitable
for submitting to upstream.
I'm going to continue looking at this issue to try to create a
more robust fix to offer upstream.
Below is a short explaination of what I've found looking into this
build failure.
The lucid build is failing with this error:
Loading /«BUILDDIR»/emacs24-24.5+1/debian/build-lucid/lisp/electric.el
(source)...
Loading /«BUILDDIR»/emacs24-24.5+1/debian/build-lucid/lisp/tooltip.el
(source)...
Finding pointers to doc strings...
Finding pointers to doc strings...done
Dumping under the name emacs
/bin/bash: line 7: 19090 Bus error ./temacs --batch --load loadup
bootstrap
make[3]: *** [bootstrap-emacs] Error 1
Makefile:815: recipe for target 'bootstrap-emacs' failed
make[3]: Leaving directory '/«BUILDDIR»/emacs24-24.5+1/debian/build-lucid/src'
make[2]: *** [src] Error 2
Makefile:389: recipe for target 'src' failed
Loading 'temacs' in gdb the bus error occurs in the file
src/unexelf.c, around line 980:
*/
if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset
|| (NEW_SECTION_H (nn).sh_offset + NEW_SECTION_H (nn).sh_size
> new_data2_offset))
NEW_SECTION_H (nn).sh_offset += new_data2_incr;
With this instruction:
0x294c20 <unexec+1204> ldx [ %g4 + 0x18 ], %g2
// info reg g4 => 0xffff80011458013b -140732852076229
So it's trying to load an extended word (64bits, 8 bytes) from an
unaligned address.
NEW_SECTION_H is a macro that generates a pointer offset from
'new_section_h'.
static void *
entry_address (void *section_h, ptrdiff_t idx, ptrdiff_t entsize)
{
char *h = section_h;
return h + idx * entsize;
}
#define NEW_SECTION_H(n) \
(*(ElfW (Shdr) *) entry_address (new_section_h, n,
new_file_h->e_shentsize))
If 'new_section_h' is properly aligned this should be ok because it's
adding multiples of 'e_shentsize' which is 8. But new_section_h is
/not/ aligned so the resulting pointer is also not aligned.
Here is how 'new_section_h' is computed:
new_section_h = (ElfW (Shdr) *)
((byte *) new_base + old_file_h->e_shoff + new_data2_incr);
GDB says the components of this sum have these values:
(gdb) print new_base
$6 = (caddr_t) 0xffff8001126aa000 "\177ELF\002\002\001"
(gdb) print old_file_h->e_shoff
$7 = 15751616
(gdb) print new_data2_incr
$8 = 16582459
'new_base' and 'old_file_h->e_shoff' are both 8 byte aligned but
'new_data2_incr' is not.
'new_data2_incr' is calculated this way:
new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
It seems like 'new_data2_incr' is just an offset so it would be ok to
round it up to the nearest multiple of 8, using a function already
used in the file:
new_data2_incr = round_up(new_data2_incr, (ElfW (Addr))8);
Adding this line to src/unexelf.c allows the build to finish normally.
-- System Information:
Debian Release: stretch/sid
APT prefers unreleased
APT policy: (500, 'unreleased'), (500, 'unstable')
Architecture: sparc64
Kernel: Linux 4.3.0-gentoo (SMP w/1 CPU core)
Locale: LANG=en_SG.UTF-8, LC_CTYPE=en_SG.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: unable to detect
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -779,6 +779,9 @@
the end of the old .data section (and thus the offset of the .bss
section) was unaligned. */
new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
+#ifdef __sparc_v9__
+ new_data2_incr = round_up(new_data2_incr, (ElfW (Addr))8);
+#endif
#ifdef UNEXELF_DEBUG
fprintf (stderr, "old_bss_index %td\n", old_bss_index);
--- End Message ---
--- Begin Message ---
Hi!
On 11/30/2015 01:29 PM, John Paul Adrian Glaubitz wrote:
> On 11/29/2015 09:47 PM, David Matthew Mattli wrote:
>> I've attached a patch that corrects an unaligned pointer dereference
>> in src/unexelf.c. But my fix is more of a hack and probably not suitable
>> for submitting to upstream.
>
> Thanks, great work! I'll upload a patched version to 'unreleased'
> which will allow packages which build-depend on emacs24 to be
> built.
The latest version of emacs24 in Debian, 24.5+1-6 now builds fine
on sparc64. I guess we can therefore close this issue and reopen
it in case the bug returns.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - [email protected]
`. `' Freie Universitaet Berlin - [email protected]
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
--- End Message ---
