From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758622AbcIWFxP (ORCPT ); Fri, 23 Sep 2016 01:53:15 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:25443 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758567AbcIWFxO (ORCPT ); Fri, 23 Sep 2016 01:53:14 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=subject:to:references:cc:from:message-id:date:user-agent:mime-version:in-reply-to:content-type; b=sbRBMIDIZkwI/PYh8KkFdx+AQl1/ozxlv0qMJlAoxdNWxbmUK8iCbmFjliiUzoU/xsOox4kxg0xR W0WVs5+4ST+KrtnBzr/Yg6+4daeby2w7Dh33Hx5nDlIWU2wbGnRw Subject: Re: [PATCH v2 1/1] lib/ioremap.c: avoid endless loop under ioremapping page unaligned ranges To: Andrew Morton References: <57E20A69.5010206@zoho.com> 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 From: zijun_hu Message-ID: <57E4C33F.4080401@zoho.com> Date: Fri, 23 Sep 2016 13:53:03 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <57E20A69.5010206@zoho.com> 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 On 09/21/2016 12:19 PM, zijun_hu wrote: > 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); > From: zijun_hu s/WARN_ON()/WARN_ON_ONCE()/ to reduce warning messages Signed-off-by: zijun_hu --- lib/ioremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/ioremap.c b/lib/ioremap.c index 911bdca..974e88b 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -129,7 +129,7 @@ int ioremap_page_range(unsigned long addr, int err; BUG_ON(addr >= end); - WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); + WARN_ON_ONCE(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); addr = round_down(addr, PAGE_SIZE); start = addr; -- 1.9.1