Date: Fri, 24 Jun 2005 21:55:34 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: current@freebsd.org Cc: Thierry Herbelot <thierry@herbelot.com> Subject: Re: Mbuf double-free guilty party detection patch Message-ID: <20050624215504.L537@odysseus.silby.com> In-Reply-To: <20050624212729.C537@odysseus.silby.com> References: <20050624212729.C537@odysseus.silby.com>
next in thread | previous in thread | raw e-mail | index | archive | help
By the way, the subject of this e-mail should be "use after free", not "double-free" - oops. Mike "Silby" Silbersack On Fri, 24 Jun 2005, Mike Silbersack wrote: > > The attached patch stores the address of who freed an mbuf/cluster/whatever > inside it, then prints that address when panicing. You can then feed that > address into "x 0xwhatever" in DDB to see who the semi-guilty party is. > > Two flaws in the patch as is: > > - It's messy and not compatible with non-i386, cleanups are needed. > > - If the mbuf in question is part of a mbuf chain, we'll see m_freem as the > guilty party, because it called m_free. > > So, if you're one of the people seeing panics due to mbufs being used after > free, please try applying the patch and see what results you get. If you keep > getting m_freem as the previous user, then I'll have to enhance it to work > around that. > > Mike "Silby" Silbersack
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050624215504.L537>