Re: [Valgrind-users] another 'cannot enable executable stack as shared object requires: Invalid argument'

[<sy...@us...>]

Thanks for the quick answer, John Reiser... I never heard of execstack
before: thanks for the pointer.

$ export ELF="`find $HOME -name '_ctypes.so'` `which valgrind`" && \
 	execstack --query $ELF && \
 	readelf -l $ELF | grep GNU_STACK

X /home/sylvain/python/lib/python2.4/site-packages/_ctypes.so
- /home/sylvain/bin/valgrind
   GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE  0x4
   GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RW   0x4

Just as you described. I added the linker parameter `-z noexecflag' while 
compiling the ctypes module, and everything is working fine now.

A subsidiary question though: I also attempted to link valgrind 
2.4.0 from CVS passing '-z execflag' to ld (by the way: right now, the 
autoconf script completely ignore command-line settings for CFLAGS). Final 
valgrind just threw back these 'cannot enable executable stack as
shared object requires' at startup on everything dynamically linked on 
the system, regardless of the stack permission in the ELF headers of 
valgrind'ed programs... I tried this too on a test machine without any 
kind of stack protection (no PIE, no SSP, no specialized 
kernel-enforcement of non-executable stack of any sort either: linux 
2.6.11, gcc 2.95, glibc 2.3.4 compiled against 2.6.11 headers with 
previous compile), same result... But just ignore this if this is not of 
any use to you: you put me right on track to investigate things myself. 
;-)

Thanks again,

-- 
Sylvain <sy...@us...>

The trouble with computers is that they do what you tell them, not what
you want.
 		-- D. Cohen