From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 20 Nov 2002 12:19:27 +0100 (CET) Received: from ftp.mips.com ([206.31.31.227]:15757 "EHLO mx2.mips.com") by linux-mips.org with ESMTP id ; Wed, 20 Nov 2002 12:19:27 +0100 Received: from newman.mips.com (ns-dmz [206.31.31.225]) by mx2.mips.com (8.12.5/8.12.5) with ESMTP id gAKBJENf014636; Wed, 20 Nov 2002 03:19:14 -0800 (PST) Received: from grendel (grendel [192.168.236.16]) by newman.mips.com (8.9.3/8.9.0) with SMTP id DAA24136; Wed, 20 Nov 2002 03:19:12 -0800 (PST) Message-ID: <00dc01c29087$319a3690$10eca8c0@grendel> From: "Kevin D. Kissell" To: "atul srivastava" Cc: References: <20021120104638.23926.qmail@webmail36.rediffmail.com> Subject: Re: epc status cause all are reported zero? Date: Wed, 20 Nov 2002 12:23:02 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4910.0300 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 679 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: kevink@mips.com Precedence: bulk X-list: linux-mips > During exec there is a page fault of 4000b0 but immediately after > that i get another page fault 0f 0x0fc01788 and following register > dump after it > fails to get a fixup address. > > Unable to handle kernel paging request at virtual address > 0fc01788, epc == 00000Oops in fault.c:do_page_fault, line 230: > $0 : 00000000 00000000 00000000 00000000 > $4 : 00007340 800f0474 00000000 801fa000 > $8 : 00000000 00000000 00000000 4c696e75 > $12: 78000000 00000000 00000000 00000000 > $16: 00000000 00000000 00000000 00000000 > $20: 00000000 00000000 00000000 00000000 > $24: 00000000 00000000 > $28: 6e652900 00000000 00000000 00000000 > epc : 00000000 > Status: 00000000 > Cause : 00000000 > Process sh (pid: 1, stackpage=801fa000) > > > i am confused how come the epc status and cause register all are > reported zero. > whether my regs ( pointer to struct pt_regs) is pointing somewhere > else..? When you see a register dump like that, it's a safe bet that your regs pointer is trashed. > secondly Is this a problem with shell or kernel..? may be > somewhere the kernel is not checking the > validity of user space address and hence this problem. By definition, it would be a kernel problem even if the shell *had* made a bogus reference. Worst case, an error in user mode should cause a core dump (of course, if it's init that dumps core, you aren't likely to get to a system login). You seem to be pretty new to this, so let me recommend that you first read the FAQ and related information at http://www.linux-mips.org/, and if you want further help from the mailing list, please specify what CPU and board/system you are targeting, which kernel sources you used, and what tools you used to build it, all of which are pretty important. Kevin K. From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <00dc01c29087$319a3690$10eca8c0@grendel> From: "Kevin D. Kissell" References: <20021120104638.23926.qmail@webmail36.rediffmail.com> Subject: Re: epc status cause all are reported zero? Date: Wed, 20 Nov 2002 12:23:02 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org To: atul srivastava Cc: linux-mips@linux-mips.org Message-ID: <20021120112302.tDAQvsAUA-ZVxBnZpULKKuXeRWOvzZH5Qu4bZlstgWA@z> > During exec there is a page fault of 4000b0 but immediately after > that i get another page fault 0f 0x0fc01788 and following register > dump after it > fails to get a fixup address. > > Unable to handle kernel paging request at virtual address > 0fc01788, epc == 00000Oops in fault.c:do_page_fault, line 230: > $0 : 00000000 00000000 00000000 00000000 > $4 : 00007340 800f0474 00000000 801fa000 > $8 : 00000000 00000000 00000000 4c696e75 > $12: 78000000 00000000 00000000 00000000 > $16: 00000000 00000000 00000000 00000000 > $20: 00000000 00000000 00000000 00000000 > $24: 00000000 00000000 > $28: 6e652900 00000000 00000000 00000000 > epc : 00000000 > Status: 00000000 > Cause : 00000000 > Process sh (pid: 1, stackpage=801fa000) > > > i am confused how come the epc status and cause register all are > reported zero. > whether my regs ( pointer to struct pt_regs) is pointing somewhere > else..? When you see a register dump like that, it's a safe bet that your regs pointer is trashed. > secondly Is this a problem with shell or kernel..? may be > somewhere the kernel is not checking the > validity of user space address and hence this problem. By definition, it would be a kernel problem even if the shell *had* made a bogus reference. Worst case, an error in user mode should cause a core dump (of course, if it's init that dumps core, you aren't likely to get to a system login). You seem to be pretty new to this, so let me recommend that you first read the FAQ and related information at http://www.linux-mips.org/, and if you want further help from the mailing list, please specify what CPU and board/system you are targeting, which kernel sources you used, and what tools you used to build it, all of which are pretty important. Kevin K.