From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lj1-f196.google.com ([209.85.208.196]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gFw24-0005Jy-FE for kexec@lists.infradead.org; Fri, 26 Oct 2018 06:55:47 +0000 Received: by mail-lj1-f196.google.com with SMTP id f3-v6so107106ljk.9 for ; Thu, 25 Oct 2018 23:55:33 -0700 (PDT) MIME-Version: 1.0 References: <20181025104017.GA29339@localhost.localdomain> In-Reply-To: <20181025104017.GA29339@localhost.localdomain> From: Bhupesh Sharma Date: Fri, 26 Oct 2018 12:25:17 +0530 Message-ID: Subject: Re: [BUG] vmcore-dmesg cant' read dmesg log from /proc/vmcore if log_buf is reallocated due to large number of CPUs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Vadim.Lomovtsev@caviumnetworks.com Cc: Vadim.Lomovtsev@cavium.com, kexec mailing list ease p before seiHi Vadim, On Thu, Oct 25, 2018 at 4:10 PM Vadim Lomovtsev wrote: > > Hello Bhupesh, > > On Thu, Oct 25, 2018 at 03:00:08AM +0530, Bhupesh Sharma wrote: > > External Email > > > > Hello Vadim, > > > > On Wed, Oct 24, 2018 at 6:23 PM Lomovtsev, Vadim > > wrote: > > > > > > Hi all, > > > > > > Following issue has been found for vmcore-dmesg app with latest release (94159bc3c264fa26395e56302072276a139d18af 2.0.18-rc1) of kexec-tools at CentOS 7.5 distro: > > > > > > While having systems with large number of CPUs (e.g. Cavium ThunderX2 has 224) the log_buf gets reallocated by memblock_virt_alloc() at the setup_log_buf routine (https://elixir.bootlin.com/linux/v4.16.18/source/kernel/printk/printk.c#L1108). > > > > > > Then while dumping vmcore the vmcore-dmesg can't find dmesg log at /proc/vmcore file and exits with following message: > > > Failed to read log text of size 0 bytes: Bad address > > > > > > However it (vmcore-dmesg app) reads properly the log_buf symbol, it's address and eventually it's value from /proc/vmcore but fails to find dmesg data then. > > > > > > In the same time the makedumpfile is able to find and extract dmesg buffer from /proc/vmcore. > > > The makedumpfile comes with kexec-tools-2.0.15-13.el7_5.2.aarch64 package. > > > > > > The issue is not reproduced for systems with small number of CPUs and log_buf not reallocated to memblock section. > > > > Seems like you are hitting a known issue we saw on qualcomm amberwing > > platforms as well. > > I have sent a patch-series titled 'kexec-tools/arm64: Add support to > > read PHYS_OFFSET from vmcoreinfo inside '/proc/kcore' to this list > > just a few minutes back. > > > > I have Cc'ed you to the patchset as I think it might fix the issue for > > you. > > Got them, thank you. > > > Kindly try the patchset on your platform (cavium?) and let me > > know if this fixes the issue for you. > > Sure, I'd like to check them at my side, but.. > I fall into merge conflicts while trying to apply them onto > https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git/ > master, kexec-tools 2.0.18-rc1 94159bc3c264fa26395e56302072276a139d18af Hmm.. that's strange as I rebased them on kexec-tools 2.0.18-rc1 (94159bc3c264fa26395e56302072276a139d18af) before sending out the patchset. > Are there any specific branch/revision for them to be applied ? > (or it might be my mail server issues with formatting emails). > Can you please try picking them up from my public github tree instead? Here you can find the same: https://github.com/bhupesh-sharma/kexec-tools/tree/read-phys-offset-from-kcore-upstream-v1 Please pick the top 2 commit from here. Thanks, Bhupesh > > > > > Thanks, > > Bhupesh _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec