From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt To: "Kevin B. Hendricks" , Anton Blanchard Cc: , Subject: Re:[PATCH]: Bug in ppc32 ld.so Date: Fri, 10 May 2002 23:13:53 +0200 Message-Id: <20020510211353.14342@smtp.wanadoo.fr> In-Reply-To: <200205101438.33701.kevin.hendricks@sympatico.ca> References: <200205101438.33701.kevin.hendricks@sympatico.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: >Hi Ben, > >Its seems Geoff Keating and Anton are debating whether this patch should >not be included in glibc and instead the new kernel behavior be reverted >to icache synchronizing zero'd pages handed out by the kernel. > >It seems Geoff thinks there may be a security risk in allowing the stale >code in the instruction cache code to be run and some benefit result by a >malicious process (not just library loading obviously). > >So people might want to wait on this patch until things get flushed out >(puin intended!). > >Either way, I would rather have a ld.so doing the complete icbi cache flush >anyway since it makes me feel safer inside! I have been bitten by too >many cache flush related errors and I favor great overkill! I fully agree with you ! Whatever we decide to do with the kernel cache flush code, let's do the proper icbi in ld.so. >The discussion is on the libc-alpha mailing list (just follow the link I >sent and go to followups at the bottom). > >Do you know where in the kernel this change was made by Paul (head.S with >the zero page code? idle.c - with its zero page code during idle, or >misc.S where the cache flush routines are now or ...). I am trying to >figure out when (what specific 2.4 kernel revision) this came into. clear_user_page, somewhere in arch/ppc/mm >Thought you might like to know. > >Thanks, > >Kevin > >On May 10, 2002 02:06, Benjamin Herrenschmidt wrote: >> >Hi Anton, >> > >> >I saw: >> > >> >http://sources.redhat.com/ml/libc-alpha/2002-05/msg00052.html >> > >> >Thanks for posting that patch. Have you by any chance alerted or sent >> >similar mail to YDL dev lists, Debian dev lists, SuSE dev lists, and >> >dev@linuxppc. >> > >> >This would be a nasty bug to track down and those distributions may >> > want to know about this and get an udpated glibc-2.2.5 packages posted >> > on their sites for those brave users who are using later 2.4 kernels? >> > >> >BTW, any idea when this change by Paul was introduced into the 2.4 >> > kernel series (specifically which 2.4.XX kernel?). >> >> I submited a debian bug report with Anton message, Olaf (suse) is on >> the linuxppc64 list and had the patch, YDL folks have or will have it >> rsn (thanks to IRC magic ;) >> >> Ben. > ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/