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[ Upstream commit 2aa958c99c7fd3162b089a1a56a34a0cdb778de1 ] Kexec-ing a kernel with "efi=noruntime" on the first kernel's command line causes the following null pointer dereference: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] Call Trace: efi_runtime_map_copy+0x28/0x30 bzImage64_load+0x688/0x872 arch_kexec_kernel_image_load+0x6d/0x70 kimage_file_alloc_init+0x13e/0x220 __x64_sys_kexec_file_load+0x144/0x290 do_syscall_64+0x55/0x1a0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Just skip the EFI info setup if EFI runtime services are not enabled. [ bp: Massage commit message. ] Suggested-by: Dave Young <dyoung@redhat.com> Signed-off-by: Kairui Song <kasong@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Young <dyoung@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: bhe@redhat.com Cc: David Howells <dhowells@redhat.com> Cc: erik.schmauss@intel.com Cc: fanc.fnst@cn.fujitsu.com Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: kexec@lists.infradead.org Cc: lenb@kernel.org Cc: linux-acpi@vger.kernel.org Cc: Philipp Rudo <prudo@linux.vnet.ibm.com> Cc: rafael.j.wysocki@intel.com Cc: robert.moore@intel.com Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Cc: Yannik Sembritzki <yannik@sembritzki.me> Link: https://lkml.kernel.org/r/20190118111310.29589-2-kasong@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.