From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932254AbcCSOQM (ORCPT ); Sat, 19 Mar 2016 10:16:12 -0400 Received: from mail.kernel.org ([198.145.29.136]:52590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753598AbcCSOPo (ORCPT ); Sat, 19 Mar 2016 10:15:44 -0400 Message-Id: <20160319141536.995426051@goodmis.org> User-Agent: quilt/0.61-1 Date: Sat, 19 Mar 2016 10:15:22 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , , Rabin Vincent Subject: [for-next][PATCH 6/8] tracing: Fix crash from reading trace_pipe with sendfile References: <20160319141516.683762867@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0006-tracing-Fix-crash-from-reading-trace_pipe-with-sendf.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (Red Hat)" If tracing contains data and the trace_pipe file is read with sendfile(), then it can trigger a NULL pointer dereference and various BUG_ON within the VM code. There's a patch to fix this in the splice_to_pipe() code, but it's also a good idea to not let that happen from trace_pipe either. Link: http://lkml.kernel.org/r/1457641146-9068-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 2.6.30+ Reported-by: Rabin Vincent Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0ae46048f724..cb2b708e4ea7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4954,7 +4954,10 @@ static ssize_t tracing_splice_read_pipe(struct file *filp, spd.nr_pages = i; - ret = splice_to_pipe(pipe, &spd); + if (i) + ret = splice_to_pipe(pipe, &spd); + else + ret = 0; out: splice_shrink_spd(&spd); return ret; -- 2.7.0