From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id B22E16B0272 for ; Fri, 23 Sep 2016 01:57:29 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id n24so204100895pfb.0 for ; Thu, 22 Sep 2016 22:57:29 -0700 (PDT) Received: from sender153-mail.zoho.com (sender153-mail.zoho.com. [74.201.84.153]) by mx.google.com with ESMTPS id t63si6057498pfi.272.2016.09.22.22.57.28 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 22 Sep 2016 22:57:28 -0700 (PDT) Subject: Re: [PATCH v2 5/5] mm/vmalloc.c: avoid endless loop under v[un]mapping improper ranges References: <57E20DCD.4000703@zoho.com> From: zijun_hu Message-ID: <57E4C439.5080701@zoho.com> Date: Fri, 23 Sep 2016 13:57:13 +0800 MIME-Version: 1.0 In-Reply-To: <57E20DCD.4000703@zoho.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton 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 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org