Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936591Ab3DHKWR (ORCPT ); Mon, 8 Apr 2013 06:22:17 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42663 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935478Ab3DHJvZ (ORCPT ); Mon, 8 Apr 2013 05:51:25 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Steven Rostedt , Lingzhu Xiang , Luis Henriques Subject: [PATCH 017/102] tracing: Protect tracer flags with trace_types_lock Date: Mon, 8 Apr 2013 10:49:32 +0100 Message-Id: <1365414657-29191-18-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1365414657-29191-1-git-send-email-luis.henriques@canonical.com> References: <1365414657-29191-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2606 Lines: 90 3.5.7.10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Lingzhu Xiang commit 69d34da2984c95b33ea21518227e1f9470f11d95 upstream. Backported for 3.4, 3.0-stable. Moved return to after unlock. From: "Steven Rostedt (Red Hat)" 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. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt Signed-off-by: Lingzhu Xiang Reviewed-by: CAI Qian Signed-off-by: Luis Henriques --- kernel/trace/trace.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 199f77b..b354405 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2791,7 +2791,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, char buf[64]; char *cmp; int neg = 0; - int ret; + int ret = 0; int i; if (cnt >= sizeof(buf)) @@ -2808,6 +2808,8 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, 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); @@ -2816,13 +2818,13 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, } /* 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; @@ -4601,7 +4603,10 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, 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; -- 1.8.1.2 -- 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/