Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762442Ab3DBWZK (ORCPT ); Tue, 2 Apr 2013 18:25:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33528 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933735Ab3DBWO2 (ORCPT ); Tue, 2 Apr 2013 18:14:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steven Rostedt , Lingzhu Xiang , CAI Qian Subject: [ 42/68] tracing: Protect tracer flags with trace_types_lock Date: Tue, 2 Apr 2013 15:13:31 -0700 Message-Id: <20130402221334.808009081@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130402221329.915209206@linuxfoundation.org> References: <20130402221329.915209206@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2306 Lines: 85 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (Red Hat)" commit 69d34da2984c95b33ea21518227e1f9470f11d95 upstream. Seems that the tracer flags have never been protected from synchronous writes. Luckily, admins don't usually modify the tracing flags via two different tasks. But if scripts were to be used to modify them, then they could get corrupted. Move the trace_types_lock that protects against tracers changing to also protect the flags being set. [Backported for 3.4, 3.0-stable. Moved return to after unlock.] Signed-off-by: Steven Rostedt Signed-off-by: Lingzhu Xiang Reviewed-by: CAI Qian Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2768,7 +2768,7 @@ tracing_trace_options_write(struct file char buf[64]; char *cmp; int neg = 0; - int ret; + int ret = 0; int i; if (cnt >= sizeof(buf)) @@ -2785,6 +2785,8 @@ tracing_trace_options_write(struct file cmp += 2; } + mutex_lock(&trace_types_lock); + for (i = 0; trace_options[i]; i++) { if (strcmp(cmp, trace_options[i]) == 0) { set_tracer_flags(1 << i, !neg); @@ -2793,13 +2795,13 @@ tracing_trace_options_write(struct file } /* If no option could be set, test the specific tracer options */ - if (!trace_options[i]) { - mutex_lock(&trace_types_lock); + if (!trace_options[i]) ret = set_tracer_option(current_trace, cmp, neg); - mutex_unlock(&trace_types_lock); - if (ret) - return ret; - } + + mutex_unlock(&trace_types_lock); + + if (ret) + return ret; *ppos += cnt; @@ -4486,7 +4488,10 @@ trace_options_core_write(struct file *fi if (val != 0 && val != 1) return -EINVAL; + + mutex_lock(&trace_types_lock); set_tracer_flags(1 << index, val); + mutex_unlock(&trace_types_lock); *ppos += cnt; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/