Date: Tue, 4 Feb 2014 17:09:57 -0500 From: Garrett Wollman <wollman@csail.mit.edu> To: "Kenneth D. Merry" <ken@freebsd.org> Cc: freebsd-scsi@freebsd.org, scottl@freebsd.org, freebsd-stable@freebsd.org Subject: Re: Heap overflow in mps(4) (was: Re: stable/9 mps(4) rev 254938 == BOOM!) Message-ID: <21233.25909.355102.743155@khavrinen.csail.mit.edu> In-Reply-To: <20140131003342.GA11755@nargothrond.kdm.org> References: <21225.19508.683025.581620@khavrinen.csail.mit.edu> <201401292137.s0TLbD5G006716@hergotha.csail.mit.edu> <20140129221514.GA47535@nargothrond.kdm.org> <21225.38749.179621.454579@khavrinen.csail.mit.edu> <20140131003342.GA11755@nargothrond.kdm.org>
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<<On Thu, 30 Jan 2014 17:33:42 -0700, "Kenneth D. Merry" <ken@freebsd.org> said: > The fact that the redzone code doesn't expose any problems makes it more > likely that it is a problem other than a heap overflow. So I built a new kernel with DEBUG_MEMGUARD. When vm.memguard.desc="mps", everything works fine both through two load/unload cycles and statically compiled into the kernel. When vm.memguard.desc is not set, instapanic as before. (I'm trying memguard rather than redzone as it has much less of a performance impact, so I can start doing some of the performance testing I was originally intending to do. Are there any debugging options that I could usefully enable that would show just what mps is doing when the fault happens? I see that there are lots of tracing options but I don't know what would actually be useful. -GAWollman
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