Date: Mon, 24 Feb 2003 13:45:09 -0800 From: "Luoqi Chen" <lchen@briontech.com> To: "Luoqi Chen" <lchen@briontech.com>, "Ulrich Spoerlein" <q@uni.de>, <freebsd-stable@FreeBSD.ORG> Subject: RE: How to debug mmap(2) with pcm(3)? Message-ID: <AHEKICEOIHLOGINAFIINMENCCAAA.lchen@briontech.com> In-Reply-To: <AHEKICEOIHLOGINAFIINEENCCAAA.lchen@briontech.com>
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> > Hello, > > > > I'm looking into the issue with mmap()ing the pcm-driver as shown in > > this PR http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/41747 . You can > > quickly verify if this bug is present on your system when you compile > > the test program Maxim Sobolev posted here > > http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&frame= > > right&th=848249298f77552a&seekm=7e40su4hduj42eufbh2e8vfahgutah94ch > > _4ax.com%40ns.sol.net#link1 > > > > Now what I want to do is, kill the bug with pcm & mmap _before_ 4.8 and > > I would need some pointers where I can start debugging this. > > > This is a "feature" of ia32 architecture, there isn't a notion of > write-only memory access, write access implies read access. If you > want to "fix" the problem with pcm device, very simple, go to file > sys/i386/trap.c and replace all occurrences of PROT_READ|PROT_WRITE > with PROT_WRITE. > > -lq > After checking with the cvs log, I realized I had checked this into -current over two years ago, and I have completely forgotten about it. I could do a MFC. Has the -stable branch been frozen yet? -lq To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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