linux-kernel - [PATCH] tracing: fix invalid function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <4A6EEAEC.3050508@cn.fujitsu.com>
Date:	Tue, 28 Jul 2009 20:11:24 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	Frederic Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] tracing: fix invalid function_graph entry


print_graph_entry() consumes current event, if this event
is the last event in the page, the ring_buffer may reuse
the page. It will become invalid.

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
---
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index abf7c4a..02102a3 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -835,9 +835,16 @@ print_graph_function(struct trace_iterator *iter)
 
 	switch (entry->type) {
 	case TRACE_GRAPH_ENT: {
-		struct ftrace_graph_ent_entry *field;
+		/*
+		 * print_graph_entry() may consume the current event,
+		 * thus @field may become invalid, so we need to save it.
+		 * sizeof(struct ftrace_graph_ent_entry) is very small,
+		 * it is safely saved at the stack.
+		 */
+		struct ftrace_graph_ent_entry *field, saved;
 		trace_assign_type(field, entry);
-		return print_graph_entry(field, s, iter);
+		saved = *field;
+		return print_graph_entry(&saved, s, iter);
 	}
 	case TRACE_GRAPH_RET: {
 		struct ftrace_graph_ret_entry *field;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/