Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752681AbaFFRVI (ORCPT ); Fri, 6 Jun 2014 13:21:08 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.231]:27385 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752648AbaFFRVG (ORCPT ); Fri, 6 Jun 2014 13:21:06 -0400 Message-Id: <20140606172104.693665166@goodmis.org> User-Agent: quilt/0.63-1 Date: Fri, 06 Jun 2014 12:30:38 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Yoshihiro YUNOMAE Subject: [for-next][PATCH 4/6] tracing: Return error if ftrace_trace_arrays list is empty References: <20140606163034.516780857@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=0003-tracing-Return-error-if-ftrace_trace_arrays-list-is-.patch X-RR-Connecting-IP: 107.14.168.130:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yoshihiro YUNOMAE ftrace_trace_arrays links global_trace.list. However, global_trace is not added to ftrace_trace_arrays if trace_alloc_buffers() failed. As the result, ftrace_trace_arrays becomes an empty list. If ftrace_trace_arrays is an empty list, current top_trace_array() returns an invalid pointer. As the result, the kernel can induce memory corruption or panic. Current implementation does not check whether ftrace_trace_arrays is empty list or not. So, in this patch, if ftrace_trace_arrays is empty list, top_trace_array() returns NULL. Moreover, this patch makes all functions calling top_trace_array() handle it appropriately. Link: http://lkml.kernel.org/p/20140605223517.32311.99233.stgit@yunodevel Signed-off-by: Yoshihiro YUNOMAE Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 3 +++ kernel/trace/trace_events.c | 13 +++++++++++++ 2 files changed, 16 insertions(+) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 217207ad60b3..9e82551dd566 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -252,6 +252,9 @@ static inline struct trace_array *top_trace_array(void) { struct trace_array *tr; + if (list_empty(ftrace_trace_arrays.prev)) + return NULL; + tr = list_entry(ftrace_trace_arrays.prev, typeof(*tr), list); WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 3ddfd8f62c05..f99e0b3bca8c 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -574,6 +574,9 @@ int trace_set_clr_event(const char *system, const char *event, int set) { struct trace_array *tr = top_trace_array(); + if (!tr) + return -ENODEV; + return __ftrace_set_clr_event(tr, NULL, system, event, set); } EXPORT_SYMBOL_GPL(trace_set_clr_event); @@ -2065,6 +2068,9 @@ event_enable_func(struct ftrace_hash *hash, bool enable; int ret; + if (!tr) + return -ENODEV; + /* hash funcs only work with set_ftrace_filter */ if (!enabled || !param) return -EINVAL; @@ -2396,6 +2402,9 @@ static __init int event_trace_enable(void) char *token; int ret; + if (!tr) + return -ENODEV; + for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) { call = *iter; @@ -2442,6 +2451,8 @@ static __init int event_trace_init(void) int ret; tr = top_trace_array(); + if (!tr) + return -ENODEV; d_tracer = tracing_init_dentry(); if (!d_tracer) @@ -2535,6 +2546,8 @@ static __init void event_trace_self_tests(void) int ret; tr = top_trace_array(); + if (!tr) + return; pr_info("Running tests on trace events:\n"); -- 2.0.0.rc2 -- 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/