From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h35Vxiqr" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33B2CCC for ; Mon, 20 Nov 2023 17:50:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700531418; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=y3Q3tLM9OGu607uvr6IkvxoBRGupiz4hQd2uNEc6wxU=; b=h35Vxiqr1QITmJY7boN3uZO1bPYrOgJMJvd+9sbm8tZ47J8t72x9BolqdjlchhsEEzXaSc EHQogQThJQNIqpBk0/VXB0ZaDI4uYCrl9PlsKDeXcgjUBGrYP+Ig+TBcgrlk7CpaV7owwd Ptne/zjbqdKAgOgfQYItq3EcjBbF464= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-317-dGxeOKufP0OB-17nBSQkQA-1; Mon, 20 Nov 2023 20:50:15 -0500 X-MC-Unique: dGxeOKufP0OB-17nBSQkQA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1F0F9811E7B; Tue, 21 Nov 2023 01:50:14 +0000 (UTC) Received: from localhost (unknown [10.72.112.97]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2267D2026D4C; Tue, 21 Nov 2023 01:50:10 +0000 (UTC) Date: Tue, 21 Nov 2023 09:50:05 +0800 From: Baoquan He To: Ignat Korchagin , eric_devolder@yahoo.com Cc: linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, geert@linux-m68k.org, tsbogend@alpha.franken.de, James Bottomley , deller@gmx.de, ysato@users.sourceforge.jp, dalias@libc.org, glaubitz@physik.fu-berlin.de, Thomas Gleixner , Ingo Molnar , Borislav Petkov , dave.hansen@linux.intel.com, x86@kernel.org, linux-kernel , linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, kernel@xen0n.name, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, hpa@zytor.com, keescook@chromium.org, paulmck@kernel.org, Peter Zijlstra , frederic@kernel.org, Andrew Morton , Ard Biesheuvel , samitolvanen@google.com, juerg.haefliger@canonical.com, arnd@arndb.de, rmk+kernel@armlinux.org.uk, linus.walleij@linaro.org, sebastian.reichel@collabora.com, rppt@kernel.org, kirill.shutemov@linux.intel.com, anshuman.khandual@arm.com, ziy@nvidia.com, masahiroy@kernel.org, ndesaulniers@google.com, mhiramat@kernel.org, ojeda@kernel.org, thunder.leizhen@huawei.com, xin3.li@intel.com, tj@kernel.org, Greg KH , tsi@tuyoix.net, hbathini@linux.ibm.com, sourabhjain@linux.ibm.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, kernel-team Subject: Re: Potential config regression after 89cde455 ("kexec: consolidate kexec and crash options into kernel/Kconfig.kexec") Message-ID: References: Precedence: bulk X-Mailing-List: linux-sh@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 Eric DeVolder's Oracle mail address is not available anymore, add his current mail address he told me. On 11/20/23 at 10:52pm, Ignat Korchagin wrote: > Good day! > > We have recently started to evaluate Linux 6.6 and noticed that we > cannot disable CONFIG_KEXEC anymore, but keep CONFIG_CRASH_DUMP > enabled. It seems to be related to commit 89cde455 ("kexec: > consolidate kexec and crash options into kernel/Kconfig.kexec"), where > a CONFIG_KEXEC dependency was added to CONFIG_CRASH_DUMP. > > In our current kernel (Linux 6.1) we only enable CONFIG_KEXEC_FILE > with enforced signature check to support the kernel crash dumping > functionality and would like to keep CONFIG_KEXEC disabled for > security reasons [1]. > > I was reading the long commit message, but the reason for adding > CONFIG_KEXEC as a dependency for CONFIG_CRASH_DUMP evaded me. And I > believe from the implementation perspective CONFIG_KEXEC_FILE should > suffice here (as we successfully used it for crashdumps on Linux 6.1). > > Is there a reason for adding this dependency or is it just an > oversight? Would some solution of requiring either CONFIG_KEXEC or > CONFIG_KEXEC_FILE work here? I searched the patch history, found Eric didn't add the dependency on CONFIG_KEXEC at the beginning. Later a linux-next building failure with randconfig was reported, in there CONFIG_CRASH_DUMP enabled, while CONFIG_KEXEC is disabled. Finally Eric added the KEXEC dependency for CRASH_DUMP. Please see below link for more details: https://lore.kernel.org/all/3e8eecd1-a277-2cfb-690e-5de2eb7b988e@oracle.com/T/#u And besides, the newly added CONFIG_CRASH_HOTPLUG also needs CONFIG_KEXEC if the elfcorehdr is allowed to be manipulated when cpu/memory hotplug hapened. Thanks Baoquan