Building of app-editors/emacs-21.4-r15 (also 18.59-r4) fails with a segmentation fault in dump-emacs / unexec. This is with the system running gentoo-sources-2.6.25-r2. The problem does not show up with 2.6.24-r7.
LC_ALL=C ./temacs -batch -l loadup dump
Finding pointers to doc strings...
Finding pointers to doc strings...done
Dumping under names emacs and emacs-21.4.1
make: *** [emacs] Segmentation fault
make: *** Deleting file `emacs'
make: Leaving directory `/var/tmp/portage/app-editors/emacs-21.4-r15/work/emacs-21.4/src'
make: *** [src] Error 2
Created attachment 152785 [details]
Created attachment 152787 [details]
Created attachment 152789 [details]
Created attachment 152791 [details, diff]
Patch for 21.4: 17_all_bss-heap-gap.patch
Patch for Emacs 21.4, backported from Emacs 22.
(A patch for Emacs 18.59 will follow later.)
Created attachment 152799 [details, diff]
Patch for 18.59: 05_all_bss-heap-gap.patch
The breakage is caused by the "randomize brk()" patch.
See the LKML, <http://lkml.org/lkml/2007/10/23/435>:
| This is known to break older versions of some emacs variants, whose
| dumper code assumed that the last variable declared in the program is
| equal to the start of the dynamically allocated memory region.
The corresponding kernel parameter is accessible via /proc/sys/kernel/randomize_va_space, the breakage occurs if its value is 2.
Fixed in emacs-18.59-r5 and emacs-21.4-r16. Leave this bug open until the fixed versions are marked stable (wrt tracker bug 218127).
Stabilisation of emacs-21.4-r17 is handled in bug 221197.
@x86: Please stabilise emacs-18.59-r5.
Preferably it should be tested with kernel 2.6.25.
x86 stable, closing