Date: Mon, 8 Jan 2001 10:36:38 +0200 (IST) From: Roman Shterenzon <roman@xpert.com> To: Greg Lehey <grog@lemis.com>, Yonatan Bokovza <yonatan@xpert.com> Cc: <hackers@freebsd.org> Subject: Re: Dump analysis (was: Ideas? (fwd)) Message-ID: <Pine.LNX.4.30.0101081031170.32287-100000@jamus.xpert.com> In-Reply-To: <20010108185709.D83353@wantadilla.lemis.com>
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On Mon, 8 Jan 2001, Greg Lehey wrote: > On Monday, 8 January 2001 at 10:04:44 +0200, Roman Shterenzon wrote: > > * Roman Shterenzon <roman@xpert.com> [010107 10:24] wrote: > >> Hi, > >> > >> Could you please take a look at : > >> http://www.freebsd.org/cgi/query-pr.cgi?pr=24019 > >> It's my friend's PR. Can you give me some hints on how can I debug this > >> issue. I'm completely puzzled here. > >> It panics on "goto out" with page fault. What I understand from it is that > >> the block at the address it tries to jmp to isn't present. But it's kernel > >> code which is never swapped out. Does it mean that the address was > >> rewritten? If it's so, what can rewrite this address? Ideas? > > My first suspicion here is that the sources are out of sync with the > kernel you're debugging. It's very important to ensure that they are This is not the case. The guy built it from the sam sources, he even used "buildkernel/installkernel" for that purpose. > absolutely in sync. Here are a couple of incantations to throw at > this dump (you may recognize the second one from an earlier mail > exchange): > > (kgdb) x/10i epread > (kgdb) x/10i 0xc012a038 > > The first one should show the beginning of the function; if it's in > sync it will look like (modulo addresses): > > (kgdb) x/10i epread > 0xc0165f8c <epread>: push %ebp > 0xc0165f8d <epread+1>: mov %esp,%ebp > 0xc0165f8f <epread+3>: sub $0x1c,%esp > 0xc0165f92 <epread+6>: push %edi > 0xc0165f93 <epread+7>: push %esi > 0xc0165f94 <epread+8>: push %ebx > 0xc0165f95 <epread+9>: mov 0x8(%ebp),%eax > 0xc0165f98 <epread+12>: mov %eax,0xfffffff4(%ebp) > 0xc0165f9b <epread+15>: mov 0x118(%eax),%edx > 0xc0165fa1 <epread+21>: add $0x8,%edx > > In particular, those first two instructions are at the beginning of > just about every function, so if you don't find them, you should check > whether your code is in sync. Yonatan, please provide the requested information. > > >> P.S. Can it be due to faulty hardware? > > Or faulty Italian cuisine? In each case, not if it's repeatable. It's repeatable, but not predictable. --Roman Shterenzon, UNIX System Administrator and Consultant [ Xpert UNIX Systems Ltd., Herzlia, Israel. Tel: +972-9-9522361 ] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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