From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935207AbZDJLJs (ORCPT ); Fri, 10 Apr 2009 07:09:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934047AbZDJLJH (ORCPT ); Fri, 10 Apr 2009 07:09:07 -0400 Received: from hera.kernel.org ([140.211.167.34]:45294 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932737AbZDJLJE (ORCPT ); Fri, 10 Apr 2009 07:09:04 -0400 Date: Fri, 10 Apr 2009 11:07:24 GMT From: Lai Jiangshan To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, fweisbec@gmail.com, srostedt@redhat.com, tglx@linutronix.de, laijs@cn.fujitsu.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, srostedt@redhat.com, tglx@linutronix.de, laijs@cn.fujitsu.com, mingo@elte.hu In-Reply-To: <49D46674.9030804@cn.fujitsu.com> References: <49D46674.9030804@cn.fujitsu.com> Subject: [tip:tracing/core] tracing: fix splice return too large Message-ID: Git-Commit-ID: 93cfb3c9fd83d877a8f1ffad9ff862b617b32828 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 10 Apr 2009 11:07:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 93cfb3c9fd83d877a8f1ffad9ff862b617b32828 Gitweb: http://git.kernel.org/tip/93cfb3c9fd83d877a8f1ffad9ff862b617b32828 Author: Lai Jiangshan AuthorDate: Thu, 2 Apr 2009 15:17:08 +0800 Committer: Ingo Molnar CommitDate: Fri, 10 Apr 2009 12:44:46 +0200 tracing: fix splice return too large I got these from strace: splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 16384 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 I wanted to splice_read 4096 bytes, but it returns 8192 or larger. It is because the return value of tracing_buffers_splice_read() does not include "zero out any left over data" bytes. But tracing_buffers_read() includes these bytes, we make them consistent. Signed-off-by: Lai Jiangshan Cc: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49D46674.9030804@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9462976..1ce5dc6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3428,7 +3428,19 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, int size, i; size_t ret; - for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) { + if (*ppos & (PAGE_SIZE - 1)) { + WARN_ONCE(1, "Ftrace: previous read must page-align\n"); + return -EINVAL; + } + + if (len & (PAGE_SIZE - 1)) { + WARN_ONCE(1, "Ftrace: splice_read should page-align\n"); + if (len < PAGE_SIZE) + return -EINVAL; + len &= PAGE_MASK; + } + + for (i = 0; i < PIPE_BUFFERS && len; i++, len -= PAGE_SIZE) { struct page *page; int r; @@ -3467,7 +3479,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, spd.partial[i].offset = 0; spd.partial[i].private = (unsigned long)ref; spd.nr_pages++; - *ppos += size; + *ppos += PAGE_SIZE; } spd.nr_pages = i;