Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755090AbcCKGbo (ORCPT ); Fri, 11 Mar 2016 01:31:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53057 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754974AbcCKGbc (ORCPT ); Fri, 11 Mar 2016 01:31:32 -0500 Message-Id: <20160311062953.623220113@redhat.com> User-Agent: quilt/0.64 Date: Fri, 11 Mar 2016 14:21:58 +0800 From: dyoung@redhat.com To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, d.hatayama@jp.fujitsu.com, bhe@redhat.com, vgoyal@redhat.com Cc: dyoung@redhat.com, kexec@lists.infradead.org Subject: [PATCH 2/2] [PATCH 2/2] proc-vmcore: wrong data type casting fix MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=0002-proc-vmcore-wrong-data-type-casting-fix.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1669 Lines: 44 On i686 PAE enabled machine the contiguous physical area could be large and it can cause triming down variables in below calculation in read_vmcore() and mmap_vmcore(): tsz = min_t(size_t, m->offset + m->size - *fpos, buflen); Then the real size passed down is not correct any more. Suppose m->offset + m->size - *fpos being truncated to 0, buflen >0 then we will get tsz = 0. It is of course not an expected result. During out test there are two problems caused by it: 1) read_vmcore will refuse to continue so makedumpfile fails. 2) mmap_vmcore will trigger BUG_ON() in remap_pfn_range(). Use min_lt instead so that the variables are not truncated. Signed-off-by: Baoquan He Signed-off-by: Dave Young --- fs/proc/vmcore.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- linux.orig/fs/proc/vmcore.c +++ linux/fs/proc/vmcore.c @@ -231,7 +231,8 @@ static ssize_t __read_vmcore(char *buffe list_for_each_entry(m, &vmcore_list, list) { if (*fpos < m->offset + m->size) { - tsz = min_t(size_t, m->offset + m->size - *fpos, buflen); + tsz = (size_t)min_lt(m->offset + m->size - *fpos, + buflen); start = m->paddr + *fpos - m->offset; tmp = read_from_oldmem(buffer, tsz, &start, userbuf); if (tmp < 0) @@ -461,7 +462,7 @@ static int mmap_vmcore(struct file *file if (start < m->offset + m->size) { u64 paddr = 0; - tsz = min_t(size_t, m->offset + m->size - start, size); + tsz = (size_t)min_lt(m->offset + m->size - start, size); paddr = m->paddr + start - m->offset; if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len, paddr >> PAGE_SHIFT, tsz,