Date: Mon, 08 Aug 2005 13:02:13 -0700 From: Nate Lawson <nate@root.org> To: csjp@FreeBSD.org Cc: cvs-src@FreeBSD.org, Don Lewis <truckman@FreeBSD.org>, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern kern_sysctl.c Message-ID: <42F7BA45.4040700@root.org> In-Reply-To: <200508081956.j78Jui1l095716@gw.catspoiler.org> References: <200508081956.j78Jui1l095716@gw.catspoiler.org>
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Don Lewis wrote: > On 8 Aug, Christian S.J. Peron wrote: >>csjp 2005-08-08 18:54:35 UTC >> >> FreeBSD src repository >> >> Modified files: >> sys/kern kern_sysctl.c >> Log: >> Check to see if we wired the user-supplied buffers in SYSCTL_OUT, if >> the buffer has not been wired and we are holding any non-sleep-able locks, >> drop a witness warning. If the buffer has not been wired, it is possible >> that the writing of the data can sleep, especially if the page is not in >> memory. This can result in a number of different locking issues, including >> dead locks. > > > Thanks. > > I think SYSCTL_IN() should also check for locks. We don't have a > function to wire the buffer in this direction. > One other thing: I don't think this should be MFCd before 6.0. It's possible that there are some drivers that violate this rule and having a release trigger panics is bad. This is the same reason we turn off INVARIANTS for releases. -- Nate
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