linux-kernel - [PATCH] tracing: Check result of ring_buffer_read

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

Message-Id: <1365558929-11211-1-git-send-email-namhyung@kernel.org>
Date:	Wed, 10 Apr 2013 10:55:29 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Namhyung Kim <namhyung.kim@....com>
Subject: [PATCH] tracing: Check result of ring_buffer_read_prepare()

From: Namhyung Kim <namhyung.kim@....com>

The ring_buffer_read_prepare() can return NULL if memory allocation
fails.  Fail out in this case instead of succedding and then having
no output.

Suggested-by: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 kernel/trace/trace.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7270460cfe3c..13200de31f0b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2826,6 +2826,8 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 		for_each_tracing_cpu(cpu) {
 			iter->buffer_iter[cpu] =
 				ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
+			if (!iter->buffer_iter[cpu])
+				goto free;
 		}
 		ring_buffer_read_prepare_sync();
 		for_each_tracing_cpu(cpu) {
@@ -2836,6 +2838,9 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 		cpu = iter->cpu_file;
 		iter->buffer_iter[cpu] =
 			ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
+		if (!iter->buffer_iter[cpu])
+			goto free;
+
 		ring_buffer_read_prepare_sync();
 		ring_buffer_read_start(iter->buffer_iter[cpu]);
 		tracing_iter_reset(iter, cpu);
@@ -2847,6 +2852,23 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 
 	return iter;
 
+free:
+	/*
+	 * For simplicity, just keep single loop without comparing cpu_file.
+	 */
+	for_each_tracing_cpu(cpu) {
+		if (iter->buffer_iter[cpu])
+			ring_buffer_read_finish(iter->buffer_iter[cpu]);
+	}
+
+	if (iter->trace && iter->trace->close)
+		iter->trace->close(iter);
+
+	if (!iter->snapshot)
+		tracing_start_tr(tr);
+
+	mutex_destroy(&iter->mutex);
+	free_cpumask_var(iter->started);
  fail:
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
-- 
1.7.11.7

--
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/