Hi! On Wed, 2011-07-20 at 06:43:51 +0000, Raphaël Hertzog wrote: > The following commit has been merged in the master branch: > commit e135afdb35d0ac179657def901965a448115a981 > Author: Raphaël Hertzog <[email protected]> > Date: Wed Jul 20 08:29:05 2011 +0200 > > dpkg: fix possible segfault in findbreakcycle(). > > The circumstances are not entirely clear because clear_istobes() is > called earlier in the code and should already ensure that clientdata > is allocated for all packages in the database but the stack trace > reported leaves no room for any other interpretation. We must protect > the access to tpkg->clientdata in findbreakcycle() with > ensure_package_clientdata(tpkg). > > Probably that some other parts of the code might create new packages in > the > in-memory database depending on some specific conditions. It might be that > those conditions only hold for a multiarch-enabled dpkg for example if > the code looks up a package entry for an alternative architecture and > would thus create the package on the fly. > > This is pure speculation because I did not push the investigations that > far. It might be something entirely different but it doesn't matter much > because the proposed fix is the same and just ensures that we respect > our API by protecting the access to clientdata. > > See https://bugs.launchpad.net/ubuntu/+source/dpkg/+bug/733414 for > details.
Hmm, trying to "fix" a bug w/o understanding the causes is almost never a good idea. In this case doubly so if this only happens in the Ubuntu dpkg. The commit might as well just be shifting the segfaults to a later point if other parts of the code are inserting new packages through pkg_db_find() or in areas where findbreakcycle() is not being used. The debian/changelog entry is also wrongly attributed. This commit is not ok and should be reverted. Something else I've been meaning to state lately is that I really want to review and ack any patch touching the dpkg C code. And just to clarify, not due to this specific commit, but it has just reminded me about it. regards, guillem -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
