From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cqekD-0003Ia-TS for kexec@lists.infradead.org; Wed, 22 Mar 2017 11:48:07 +0000 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v2MBhYPw074446 for ; Wed, 22 Mar 2017 07:47:40 -0400 Received: from e28smtp09.in.ibm.com (e28smtp09.in.ibm.com [125.16.236.9]) by mx0a-001b2d01.pphosted.com with ESMTP id 29b9vsg9ec-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 22 Mar 2017 07:47:39 -0400 Received: from localhost by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Mar 2017 17:17:06 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay08.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2MBjnur15466644 for ; Wed, 22 Mar 2017 17:15:49 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v2MBl2hu016163 for ; Wed, 22 Mar 2017 17:17:02 +0530 Subject: Re: [PATCH v3 1/3] kexec: Move vmcoreinfo out of the kernel's .bss section References: <1489989033-1179-1-git-send-email-xlpang@redhat.com> <87pohbz4lo.fsf@xmission.com> <20170322025536.GA4424@dhcp-128-65.nay.redhat.com> <87pohaxam1.fsf@xmission.com> <20170322043004.GB4424@dhcp-128-65.nay.redhat.com> From: Hari Bathini Date: Wed, 22 Mar 2017 17:16:56 +0530 MIME-Version: 1.0 In-Reply-To: <20170322043004.GB4424@dhcp-128-65.nay.redhat.com> Message-Id: <0e9381e2-a44e-aa48-6463-45b571222203@linux.vnet.ibm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Young , "Eric W. Biederman" Cc: Baoquan He , Xunlei Pang , Atsushi Kumagai , Petr Tesarik , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, holzheu@linux.vnet.ibm.com, kexec@lists.infradead.org Hi Dave, On Wednesday 22 March 2017 10:00 AM, Dave Young wrote: > On 03/21/17 at 10:18pm, Eric W. Biederman wrote: >> Dave Young writes: >> >>> On 03/20/17 at 10:33pm, Eric W. Biederman wrote: >>>> Xunlei Pang writes: >>>> >>>>> As Eric said, >>>>> "what we need to do is move the variable vmcoreinfo_note out >>>>> of the kernel's .bss section. And modify the code to regenerate >>>>> and keep this information in something like the control page. >>>>> >>>>> Definitely something like this needs a page all to itself, and ideally >>>>> far away from any other kernel data structures. I clearly was not >>>>> watching closely the data someone decided to keep this silly thing >>>>> in the kernel's .bss section." >>>>> >>>>> This patch allocates extra pages for these vmcoreinfo_XXX variables, >>>>> one advantage is that it enhances some safety of vmcoreinfo, because >>>>> vmcoreinfo now is kept far away from other kernel data structures. >>>> Can you preceed this patch with a patch that removes CRASHTIME from >>>> vmcoreinfo? If someone actually cares we can add a separate note that holds >>>> a 64bit crashtime in the per cpu notes. >>> I think makedumpfile is using it, but I also vote to remove the >>> CRASHTIME. It is better not to do this while crashing and a makedumpfile >>> userspace patch is needed to drop the use of it. >>> >>>> As we are looking at reliability concerns removing CRASHTIME should make >>>> everything in vmcoreinfo a boot time constant. Which should simplify >>>> everything considerably. >>> It is a nice improvement.. >> We also need to take a close look at what s390 is doing with vmcoreinfo. >> As apparently it is reading it in a different kind of crashdump process. > Yes, need careful review from s390 and maybe ppc64 especially about > patch 2/3, better to have comments from IBM about s390 dump tool and ppc > fadump. Added more cc. w.r.t powerpc/fadump, this patch-set works fine.. Thanks Hari _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec