From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from g4t0015.houston.hp.com ([15.201.24.18]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vg2qL-00077V-10 for kexec@lists.infradead.org; Tue, 12 Nov 2013 01:32:37 +0000 Message-ID: <1384219658.1847.84.camel@misato.fc.hp.com> Subject: Re: [patch 1/3 v2] Add function get_bootparam From: Toshi Kani Date: Mon, 11 Nov 2013 18:27:38 -0700 In-Reply-To: <20131105083428.411624560@dhcp-16-126.nay.redhat.com> References: <20131105082947.500512312@dhcp-16-126.nay.redhat.com> <20131105083428.411624560@dhcp-16-126.nay.redhat.com> Mime-Version: 1.0 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=twosheds.infradead.org@lists.infradead.org To: dyoung@redhat.com Cc: mjg59@srcf.ucam.org, linux-efi@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, James.Bottomley@HansenPartnership.com, horms@verge.net.au, bp@alien8.de, ebiederm@xmission.com, hpa@zytor.com, vgoyal@redhat.com On Tue, 2013-11-05 at 16:29 +0800, dyoung@redhat.com wrote: > Not only setup_subarch will get data from debugfs file > boot_params/data, later code for adding efi_info will > also need do same thing. Thus add a common function here > for later use. get_bootparam() calls find_mnt_by_fsname("debugfs"), which assumes that debugfs is mounted with device name "debugfs". This function fails when: - debugfs is not mounted, or - debugfs is mounted with a different device name, such as nodev [1]. This issue is not introduced by this patch. But the original code, which sets hardware_subarch, seems to work even if it failed to access debugfs (which is ignored) since hardware_subarch is zero most of the cases anyway. With this change, however, this failure now makes the 2nd kernel unbootable. So, it needs to be addressed to make this code path work reliably (or kexec should fail at least). [1] https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_MRG/2/html/Realtime_Tuning_Guide/sect-Realtime_Tuning_Guide-Realtime_Specific_Tuning-Mount_debugfs.html Thanks, Toshi _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec