From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758458AbcIWF50 (ORCPT ); Fri, 23 Sep 2016 01:57:26 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:25367 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753542AbcIWF5Z (ORCPT ); Fri, 23 Sep 2016 01:57:25 -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=Bv7kT+zJuAb7eDgMcEUydA/gGr4W/b0evaRCfx5J++qfHVn8TOxRgA5AA9nPMH3vK2Zlvdm18bVb Ly5VP26Ke+FPi5v5q0CA3TQdoj8wtSlUothVj+bUdghZDxTVqiX9 Subject: Re: [PATCH v2 5/5] mm/vmalloc.c: avoid endless loop under v[un]mapping improper ranges To: Andrew Morton References: <57E20DCD.4000703@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: <57E4C439.5080701@zoho.com> Date: Fri, 23 Sep 2016 13:57:13 +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: <57E20DCD.4000703@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 12:34 PM, zijun_hu wrote: > From: zijun_hu > > fix the following bug: > - endless loop maybe happen when v[un]mapping improper ranges > whose either boundary is not aligned to page > > Signed-off-by: zijun_hu > --- > mm/vmalloc.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 5eeecc3..16fe957 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -67,7 +67,7 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end) > do { > pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte); > WARN_ON(!pte_none(ptent) && !pte_present(ptent)); > - } while (pte++, addr += PAGE_SIZE, addr != end); > + } while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE); > } > > static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end) > @@ -108,6 +108,9 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) > unsigned long next; > > BUG_ON(addr >= end); > + WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); > + > + addr = round_down(addr, PAGE_SIZE); > pgd = pgd_offset_k(addr); > do { > next = pgd_addr_end(addr, end); > @@ -139,7 +142,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, > return -ENOMEM; > set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); > (*nr)++; > - } while (pte++, addr += PAGE_SIZE, addr != end); > + } while (pte++, addr += PAGE_SIZE, addr < end); > return 0; > } > > @@ -193,6 +196,8 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end, > int nr = 0; > > BUG_ON(addr >= end); > + BUG_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); > + > pgd = pgd_offset_k(addr); > do { > next = pgd_addr_end(addr, end); > From: zijun_hu s/WARN_ON()/WARN_ON_ONCE()/ to reduce warning messages Signed-off-by: zijun_hu --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 16fe957..e34031e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -108,7 +108,7 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) unsigned long next; 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); pgd = pgd_offset_k(addr); -- 1.9.1