From patchwork Wed Feb 16 06:06:41 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li Zefan X-Patchwork-Id: 565821 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p1G6DIWP032548 for ; Wed, 16 Feb 2011 06:13:19 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752971Ab1BPGNN (ORCPT ); Wed, 16 Feb 2011 01:13:13 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:61627 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752427Ab1BPGNK (ORCPT ); Wed, 16 Feb 2011 01:13:10 -0500 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id 216E3170146; Wed, 16 Feb 2011 14:13:06 +0800 (CST) Received: from mailserver.fnst.cn.fujitus.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id p1G67KoO020987; Wed, 16 Feb 2011 14:07:26 +0800 Received: from [10.167.225.230] ([10.167.225.230]) by mailserver.fnst.cn.fujitus.com (Lotus Domino Release 8.5.1FP4) with ESMTP id 2011021614042590-148323 ; Wed, 16 Feb 2011 14:04:25 +0800 Message-ID: <4D5B6971.2040006@cn.fujitsu.com> Date: Wed, 16 Feb 2011 14:06:41 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: "linux-btrfs@vger.kernel.org" CC: Juan Francisco Cantero Hurtado Subject: [PATCH 2/2] Btrfs: Avoid accessing unmapped kernel address X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-16 14:04:26, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-16 14:12:10, Serialize complete at 2011-02-16 14:12:10 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 16 Feb 2011 06:13:19 +0000 (UTC) diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index cc9b450..a178f5e 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -280,6 +280,7 @@ static int lzo_decompress_biovec(struct list_head *ws, unsigned long tot_out; unsigned long tot_len; char *buf; + bool may_late_unmap, need_unmap; data_in = kmap(pages_in[0]); tot_len = read_compress_length(data_in); @@ -300,11 +301,13 @@ static int lzo_decompress_biovec(struct list_head *ws, tot_in += in_len; working_bytes = in_len; + may_late_unmap = need_unmap = false; /* fast path: avoid using the working buffer */ if (in_page_bytes_left >= in_len) { buf = data_in + in_offset; bytes = in_len; + may_late_unmap = true; goto cont; } @@ -329,14 +332,17 @@ cont: if (working_bytes == 0 && tot_in >= tot_len) break; - kunmap(pages_in[page_in_index]); - page_in_index++; - if (page_in_index >= total_pages_in) { + if (page_in_index + 1 >= total_pages_in) { ret = -1; - data_in = NULL; goto done; } - data_in = kmap(pages_in[page_in_index]); + + if (may_late_unmap) + need_unmap = true; + else + kunmap(pages_in[page_in_index]); + + data_in = kmap(pages_in[++page_in_index]); in_page_bytes_left = PAGE_CACHE_SIZE; in_offset = 0; @@ -346,6 +352,8 @@ cont: out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE); ret = lzo1x_decompress_safe(buf, in_len, workspace->buf, &out_len); + if (need_unmap) + kunmap(pages_in[page_in_index - 1]); if (ret != LZO_E_OK) { printk(KERN_WARNING "btrfs decompress failed\n"); ret = -1; @@ -363,8 +371,7 @@ cont: break; } done: - if (data_in) - kunmap(pages_in[page_in_index]); + kunmap(pages_in[page_in_index]); return ret; }