Date: Fri, 20 Jan 2006 02:22:47 -0500 From: Joe Marcus Clarke <marcus@FreeBSD.org> To: Jason Evans <jasone@FreeBSD.org> Cc: freebsd-current@FreeBSD.org Subject: Re: Typical malloc-related application bugs Message-ID: <1137741767.75264.27.camel@shumai.marcuscom.com> In-Reply-To: <6BD97F93-5E85-4A5A-8751-DC0C0382B916@FreeBSD.org> References: <6BD97F93-5E85-4A5A-8751-DC0C0382B916@FreeBSD.org>
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[-- Attachment #1 --] On Thu, 2006-01-19 at 23:10 -0800, Jason Evans wrote: > Overall, the malloc changeover has been pretty uneventful. Now that > jemalloc has seen a bit wider exposure, I thought it might be useful > to summarize the types of application bugs that it has been uncovering. First let me say that jemalloc has found quite a few bugs in GNOME applications that were not spotted with phkmalloc+AJ. I only wish those bugs had not been there to begin with :-}. [snip] > 2) Out-of-bounds writes. Lots of programs have been found to write > past the end of the space they allocate. At the moment, jemalloc's > redzone code is enabled, so these errors are causing messages to > stderr that look like: > > ifconfig: (malloc) Corrupted redzone 1 byte after 0xa000150 (size > 18) (0x0) > > In at least one case (running f2c while building the math/arpack > port), these overruns would have caused actual malloc data structure > corruption, had redzones not been enabled. I'm seeing a lot of this when I run gnome-system-monitor. There appears to be a bug in libgtop, but I don't know how to make these messages fatal in order to produce a backtrace I can use to narrow down where the problem lies. What can I do to isolate where in the code the redzone corruption is occurring? Additionally, do you have any example code that produces this kind of redzone corruption? Thanks. Joe -- Joe Marcus Clarke FreeBSD GNOME Team :: gnome@FreeBSD.org FreeNode / #freebsd-gnome http://www.FreeBSD.org/gnome [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQBD0I/Hb2iPiv4Uz4cRAghxAJ41q91vfuSeJOYTVHARJReb6oG3xQCfY4Zn J3CwsSgI11LNlgokaTB4oXM= =+T57 -----END PGP SIGNATURE-----help
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