Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760046Ab2BJTwT (ORCPT ); Fri, 10 Feb 2012 14:52:19 -0500 Received: from gw.danplanet.com ([50.43.125.66]:41942 "EHLO mail.danplanet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759958Ab2BJTwS (ORCPT ); Fri, 10 Feb 2012 14:52:18 -0500 X-Greylist: delayed 731 seconds by postgrey-1.27 at vger.kernel.org; Fri, 10 Feb 2012 14:52:18 EST From: Dan Smith To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned Date: Fri, 10 Feb 2012 11:39:56 -0800 Message-Id: <1328902796-30389-1-git-send-email-danms@us.ibm.com> X-Mailer: git-send-email 1.7.9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1294 Lines: 39 The inner function walk_pte_range() increments "addr" by PAGE_SIZE after each pte is processed, and only exits the loop if the result is equal to "end". Current, if either (or both of) the starting or ending addresses passed to walk_page_range() are not page-aligned, then we will never satisfy that exit condition and begin calling the pte_entry handler with bad data. To be sure that we will land in the right spot, this patch checks that both "addr" and "end" are page-aligned in walk_page_range() before starting the traversal. Signed-off-by: Dan Smith Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/pagewalk.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 2f5cf10..9242bfc 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -196,6 +196,8 @@ int walk_page_range(unsigned long addr, unsigned long end, if (addr >= end) return err; + VM_BUG_ON((addr & ~PAGE_MASK) || (end & ~PAGE_MASK)); + if (!walk->mm) return -EINVAL; -- 1.7.9 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/