From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wi0-f181.google.com ([209.85.212.181]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZS43s-0000NB-9E for kexec@lists.infradead.org; Wed, 19 Aug 2015 14:09:56 +0000 Received: by wicne3 with SMTP id ne3so128117941wic.1 for ; Wed, 19 Aug 2015 07:09:28 -0700 (PDT) Subject: Re: Dmesg not being dumped References: <55D42056.5070709@kyup.com> <20150819131302.GA11631@dhcp-128-25.nay.redhat.com> <55D48768.4020207@kyup.com> <20150819140809.GB11631@dhcp-128-25.nay.redhat.com> From: Nikolay Borisov Message-ID: <55D48E16.5050304@kyup.com> Date: Wed, 19 Aug 2015 17:09:26 +0300 MIME-Version: 1.0 In-Reply-To: <20150819140809.GB11631@dhcp-128-25.nay.redhat.com> 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: Minfei Huang Cc: kexec@lists.infradead.org On 08/19/2015 05:08 PM, Minfei Huang wrote: > On 08/19/15 at 04:40pm, Nikolay Borisov wrote: >> On 08/19/2015 04:13 PM, Minfei Huang wrote: >>> Hi. Nikolay. >>> Does kexec-tools work for original rhel kernel, like 3.10.0-xxx. Also do >> >> Unfortunately I canno test with an official rhel kernel since we are not >> using those. Also, the problem is not that kexec is not working at all, >> but just that the dmesg log is not being saved in the vmcore-dmesg.txt >> file. Here are the relevant portion of the my .config which deal with >> debug info: >> >> CONFIG_DEBUG_INFO=y >> # CONFIG_DEBUG_INFO_REDUCED is not set >> # CONFIG_DEBUG_INFO_SPLIT is not set >> # CONFIG_DEBUG_INFO_DWARF4 is not set > > I ran the kexec-tools-2.0.7-35 on kernel 4.2.0-rc5+ and kdump works > successfully to dump the vmcore. The kernel is built by the default config > (generated by make defconfig). Following is the relevant portions of the > config. > > # cat .config | grep KEXEC > CONFIG_KEXEC=y > CONFIG_KEXEC_FILE=y > CONFIG_KEXEC_VERIFY_SIG=y > CONFIG_KEXEC_BZIMAGE_VERIFY_SIG=y > CONFIG_KEXEC_JUMP=y > # cat .config | grep DEBUG_INFO > CONFIG_DEBUG_INFO=y > # CONFIG_DEBUG_INFO_REDUCED is not set > # CONFIG_DEBUG_INFO_SPLIT is not set > # CONFIG_DEBUG_INFO_DWARF4 is not set > > Thanks > Minfei I only have CONFIG_KEXEC=y but the others are not necessary as far as I can tell. I don't do any verification so the VERIFY_SIG are disabled. KEXEC_JUMP is also n, since I haven't enabled hibernation and KEXEC_FILE is also not critical. My debug info is the same as yours. > >> >> The failures is happening (according to my reading of the vmcore-dmesg.c >> file) here: >> >> + if (!log_sz) { >> + fprintf(stderr, "Missing the struct log size export\n"); >> + exit(64); >> + } >> >> And log_size is being set here: >> >> str = "SIZE(printk_log)="; >> if (memcmp(str, pos, strlen(str)) == 0) >> log_sz = strtoull(pos + strlen(str), NULL, 10); >> >> The pertinent question I guess is why this string cannot be found in the >> resulting vmcore image. I just tried with kexec 2.0.10 and the result is >> the same. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec