comments, summary, then some more details: comments: With >>100x performance hit (>500x typical), but apparently not present in oldstalbe, but present in stable, I'm guestimating this bug should be important or critical. I've not determined full scope of bug. I may or may not manage to (e.g. time, priorities) find/develop patch, but it would be really nice :-) to have a patch on this for stable to correct this bug. As/when I'm able, I'm looking towards a minimal patch that will correct this bug, but not otherwise alter stable (at least if/as such may be feasible).
summary: bug appears to be upstream, bug appears to be problem in function dfaexec bug appears present in GNU grep-2.6.3 bug appears to be gone in GNU grep-2.7 copying: src/dfa.c src/dfa.h src/dfasearch.c from GNU grep-2.7 to GNU grep-2.6.3 causes bug to go away in GNU grep-2.6.3 (but no guarantees that doesn't potentially introduce other issues). That's as far as I've isolated it thus far. details: on getting to the above point (in approximate reverse order): The above and below tests were all done on currently patched Debian stable amd64. Copying the src/dfa* files from unpatched GNU grep-2.6.3 to unpatched GNU grep-2.7 appears to make the bug go away in grep-2.6.3 (no guarantees regarding other impacts). Searched for dfaexec in clean (make distclean) source for above and examined and compared files - seemed limited to, at most the three src/dfa* files; file differences appeared rather non-trivial; as experiment, tried copy as noted to see if it would even compile and function, and possibly squash bug. Compiling for debugging and profiling: CFLAGS='-ggdb -pg' ./configure and executing and examining profile (gprof(1)) indicated major performance problem in dfaexec function. Testing various unpatched released GNU grep versions showed bug apparently present in GNU grep-2.6.3 but apparently not present in GNU grep-2.7 (and subsequent versions). Testing unpatched upstream (orig) from Debian: http://ftp.de.debian.org/debian/pool/main/g/grep/grep_2.6.3.orig.tar.bz2 http://ftp.de.debian.org/debian/pool/main/g/grep/grep_2.9.orig.tar.gz showed bug present in 2.6.3 but not 2.9. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
