Date: Sun, 21 Oct 2012 21:28:06 +0300 From: Alexander Motin <mav@FreeBSD.org> To: David Wolfskill <david@catwhisker.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, stable@freebsd.org Subject: Re: stable/9 @r241776 panic: REDZONE: Buffer underflow detected... Message-ID: <50843EB6.8030407@FreeBSD.org> In-Reply-To: <20121021174054.GM35915@deviant.kiev.zoral.com.ua> References: <20121020141019.GW1817@albert.catwhisker.org> <20121021121356.GJ35915@deviant.kiev.zoral.com.ua> <20121021163322.GB1730@albert.catwhisker.org> <20121021164634.GC1730@albert.catwhisker.org> <20121021174054.GM35915@deviant.kiev.zoral.com.ua>
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On 21.10.2012 20:40, Konstantin Belousov wrote: > On Sun, Oct 21, 2012 at 09:46:34AM -0700, David Wolfskill wrote: >> On Sun, Oct 21, 2012 at 09:33:22AM -0700, David Wolfskill wrote: >>> ... >>> So I tried reverting 241749 ... and I failed to reproduce the problem. >>> >>> Well, one boot out of one, at least. I'll try a few more reality >>> checks, and report back if a correction is in order. But (for now, at >>> least), it looks to me as if 241749 is presenting a problem on this >>> laptop. >>> ... >> >> 5 for 5. I'm convinced that 241749 causes problems on this laptop for >> attempts to boot without a stop is single-user mode first. >> >> (So that sounds like a timing issue, somehow.) >> >> And thanks again, Konstantin! > > I do not know/do not understand the CAM code, the question shall > be addressed to Alexander. It still might be a false positive. I don't see how increasing buffer size by few bytes in mentioned change may cause memory corruption in some other place. I guess change can be just innocent witness that affected some memory placement, moving some existing corruption from one area to another where it was noticed. I am curious, how to interpret phrase "42=94966796 bytes allocated" in log. May be it is just corrupted output, but the number still seems quite big, especially for i386 system, making me think about some integer overflow. David, could you write down that part once more? Having few more lines of "Allocation backtrace:" could also be useful. Could you show your kernel config? I can try to run it on my tests system, hoping to reproduce the problem. -- Alexander Motin
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