From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752472Ab0IPE6i (ORCPT ); Thu, 16 Sep 2010 00:58:38 -0400 Received: from mx3-phx2.redhat.com ([209.132.183.24]:34333 "EHLO mx01.colomx.prod.int.phx2.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750714Ab0IPE6h (ORCPT ); Thu, 16 Sep 2010 00:58:37 -0400 Date: Thu, 16 Sep 2010 00:57:58 -0400 (EDT) From: caiqian@redhat.com To: tj@kernel.org Cc: linux-kernel , kexec , graff.yang@gmail.com, Marcelo Tosatti , dhowells@redhat.com, sonic.adi@gmail.com, Avi Kivity , Chris Lalancette , stable@kernel.org, Cliff Wickman Message-ID: <1301046921.1075601284613078206.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> In-Reply-To: <387799126.1075471284612953135.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> Subject: [PATCH] fix kvm kdump regression MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.5.5.72] X-Mailer: Zimbra 5.0.21_GA_3150.RHEL4_64 (ZimbraWebClient - FF3.0 (Linux)/5.0.21_GA_3150.RHEL4_64) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 020ec6537aa65c18e9084c568d7b94727f2026fd introduced a regression that an empty vmcore was generated during kdump on a kvm guest. ioremap: invalid physical address db74000000000000 ------------[ cut here ]------------ WARNING: at arch/x86/mm/ioremap.c:83 __ioremap_caller+0x307/0x380() Hardware name: KVM Modules linked in: Pid: 1, comm: swapper Not tainted 2.6.36-rc2-mm1+ #2 Call Trace: [] warn_slowpath_common+0x7f/0xc0 [] ? copy_oldmem_page+0x4e/0xc0 [] warn_slowpath_null+0x1a/0x20 [] __ioremap_caller+0x307/0x380 [] ioremap_nocache+0x17/0x20 [] copy_oldmem_page+0x4e/0xc0 [] read_from_oldmem+0x7a/0xb0 [] merge_note_headers_elf64.clone.1+0x6c/0x21f [] ? copy_oldmem_page+0x8e/0xc0 [] ? read_from_oldmem+0x7a/0xb0 [] vmcore_init+0x19d/0x396 [] ? vmcore_init+0x0/0x396 [] do_one_initcall+0x43/0x190 [] kernel_init+0x2a0/0x330 [] kernel_thread_helper+0x4/0x10 [] ? kernel_init+0x0/0x330 [] ? kernel_thread_helper+0x0/0x10 ---[ end trace 93d72a36b9146f22 ]--- Kdump: vmcore not initialized This patch fixed it by reverting a chunk of the above commit and 9983b6f0cf8263e51bcf4c8a9dc0c1ef175b3c60 which is based on it. Signed-off-by: CAI Qian diff --git a/mm/percpu.c b/mm/percpu.c index 77e3f5a..0dbb12a 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -986,38 +986,10 @@ bool is_kernel_percpu_address(unsigned long addr) */ phys_addr_t per_cpu_ptr_to_phys(void *addr) { - void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); - bool in_first_chunk = false; - unsigned long first_start, first_end; - unsigned int cpu; - - /* - * The following test on first_start/end isn't strictly - * necessary but will speed up lookups of addresses which - * aren't in the first chunk. - */ - first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0); - first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu, - pcpu_unit_pages); - if ((unsigned long)addr >= first_start && - (unsigned long)addr < first_end) { - for_each_possible_cpu(cpu) { - void *start = per_cpu_ptr(base, cpu); - - if (addr >= start && addr < start + pcpu_unit_size) { - in_first_chunk = true; - break; - } - } - } - - if (in_first_chunk) { - if ((unsigned long)addr < VMALLOC_START || - (unsigned long)addr >= VMALLOC_END) - return __pa(addr); - else - return page_to_phys(vmalloc_to_page(addr)); - } else + if ((unsigned long)addr < VMALLOC_START || + (unsigned long)addr >= VMALLOC_END) + return __pa(addr); + else return page_to_phys(pcpu_addr_to_page(addr)); }