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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id p85sm17740577wme.23.2019.09.28.05.41.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 28 Sep 2019 05:41:31 -0700 (PDT) Date: Sat, 28 Sep 2019 14:41:29 +0200 From: Ingo Molnar To: Randy Dunlap Cc: Andreas Smas , linux-kernel@vger.kernel.org, X86 ML Subject: Re: x86/purgatory: undefined symbol __stack_chk_fail Message-ID: <20190928124129.GA97534@gmail.com> References: <6c46ae4d-6837-d1a3-dbe0-03a9efcb862f@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6c46ae4d-6837-d1a3-dbe0-03a9efcb862f@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Randy Dunlap wrote: > On 9/3/19 8:50 AM, Andreas Smas wrote: > > Hi, > > > > For me, kernels built including this commit > > b059f801a937 (x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS) > > > > results in kexec() failing to load the kernel: > > > > kexec: Undefined symbol: __stack_chk_fail > > kexec-bzImage64: Loading purgatory failed > > > > Can be seen: > > > > $ readelf -a arch/x86/purgatory/purgatory.ro | grep UND > > 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND > > 51: 0000000000000000 0 NOTYPE GLOBAL DEFAULT UND __stack_chk_fail > > > > Using: gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1) > > > > Adding -ffreestanding or -fno-stack-protector to ccflags-y in > > arch/x86/purgatory/Makefile > > fixes the problem. Not sure which would be preferred. > > > > Hi, > Do you have a kernel .config file that causes this? > I can't seem to reproduce it. Does it go away with this fix in x86/urgent: ca14c996afe7: ("x86/purgatory: Disable the stackleak GCC plugin for the purgatory") git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent ? Thanks, Ingo