From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669AbcIUEU4 (ORCPT ); Wed, 21 Sep 2016 00:20:56 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:25475 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753367AbcIUEUx (ORCPT ); Wed, 21 Sep 2016 00:20:53 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=cc:to:from:subject:message-id:date:user-agent:mime-version:content-type; b=D5B1og1C4rdHh6nYrqJX8W2Gk/vJXc1vw+eP59v2wjRKK5XvA3n/E4bkBGkh6qtC3HbuKcEn/1KH nX4Q7ZUSOwZQO1vDp5K44EDt5E3jgUEt8v3g2HWTPlKPX/fCJB7t Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, zijun_hu@htc.com, tj@kernel.org, mingo@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net To: Andrew Morton From: zijun_hu Subject: [PATCH 1/1] lib/ioremap.c: avoid endless loop under ioremapping page unaligned ranges Message-ID: <57E20A69.5010206@zoho.com> Date: Wed, 21 Sep 2016 12:19:53 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: zijun_hu endless loop maybe happen if either of parameter addr and end is not page aligned for kernel API function ioremap_page_range() in order to fix this issue and alert improper range parameters to user WARN_ON() checkup and rounding down range lower boundary are performed firstly, loop end condition within ioremap_pte_range() is optimized due to lack of relevant macro pte_addr_end() Signed-off-by: zijun_hu --- lib/ioremap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lib/ioremap.c b/lib/ioremap.c index 86c8911..911bdca 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -64,7 +64,7 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, BUG_ON(!pte_none(*pte)); set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); pfn++; - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE); return 0; } @@ -129,7 +129,9 @@ int ioremap_page_range(unsigned long addr, int err; BUG_ON(addr >= end); + WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); + addr = round_down(addr, PAGE_SIZE); start = addr; phys_addr -= addr; pgd = pgd_offset_k(addr); -- 1.9.1