Date: Sun, 01 Oct 2006 15:37:19 -0500 From: Alan Cox <alc@cs.rice.edu> To: Martin Blapp <mb@imp.ch> Cc: Alan Cox <alc@FreeBSD.org>, cvs-src@FreeBSD.org, src-committers@FreeBSD.org, re@freesbd.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/amd64/amd64 pmap.c src/sys/i386/i386 pmap.c Message-ID: <452026FF.9040000@cs.rice.edu> In-Reply-To: <20061001191543.M91466@godot.imp.ch> References: <200609271810.k8RIAGSu022079@repoman.freebsd.org> <20061001191543.M91466@godot.imp.ch>
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Martin Blapp wrote: > > Hi Alan, > > This commit makes my box crash with HEAD at startup. Please back it out > and investige why it happens. I'm pretty sure that it happens for > RELENG_6 too. > The assertion that fails for you under HEAD does not exist in RELENG_6. Have you seen a different assertion failure or crash in RELENG_6 since this patch was applied there? I will discuss this with re@. Regards, Alan > > > Martin Blapp, <mb@imp.ch> <mbr@FreeBSD.org> > ------------------------------------------------------------------ > ImproWare AG, UNIXSP & ISP, Zurlindenstrasse 29, 4133 Pratteln, CH > Phone: +41 61 826 93 00 Fax: +41 61 826 93 01 > PGP: <finger -l mbr@freebsd.org> > PGP Fingerprint: B434 53FC C87C FE7B 0A18 B84C 8686 EF22 D300 551E > ------------------------------------------------------------------ > > On Wed, 27 Sep 2006, Alan Cox wrote: > >> alc 2006-09-27 18:10:16 UTC >> >> FreeBSD src repository >> >> Modified files: (Branch: RELENG_6) >> sys/amd64/amd64 pmap.c >> sys/i386/i386 pmap.c >> Log: >> MFC >> Correct a very old and very obscure bug: vmspace_fork() calls >> pmap_copy() if the mapping is VM_INHERIT_SHARE. Suppose the mapping >> is also wired. vmspace_fork() clears the wiring attributes in the vm >> map entry but pmap_copy() copies the PG_W attribute in the PTE. I >> don't think this is catastrophic. It blocks pmap_remove_pages() from >> destroying the mapping and corrupts the pmap's wiring count. >> >> This revision fixes the problem by changing pmap_copy() to clear the >> PG_W attribute. >> >> Approved by: re (mux) >> >> Revision Changes Path >> 1.516.2.8 +4 -3 src/sys/amd64/amd64/pmap.c >> 1.523.2.8 +5 -3 src/sys/i386/i386/pmap.c >>
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