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authorSteven Rostedt <srostedt@redhat.com>2009-02-18 22:50:01 -0500
committerSteven Rostedt <srostedt@redhat.com>2009-02-18 22:50:01 -0500
commit4b3e3d228429c75d398f1aa24532e468d3220c49 (patch)
treeff0f2bd4b3f6903ad563d16c47d0bbb15603b2dd
parent4d7a077c0c7bfdba04cf0aa0b79053cf4ebaacf8 (diff)
tracing: limit the number of loops the ring buffer self test can make
Impact: prevent deadlock if ring buffer gets corrupted This patch adds a paranoid check to make sure the ring buffer consumer does not go into an infinite loop. Since the ring buffer has been set to read only, the consumer should not loop for more than the ring buffer size. A check is added to make sure the consumer does not loop more than the ring buffer size. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
-rw-r--r--kernel/trace/trace_selftest.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index a7e0ef662f9f..bc8e80a86bca 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -23,10 +23,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
{
struct ring_buffer_event *event;
struct trace_entry *entry;
+ unsigned int loops = 0;
while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
entry = ring_buffer_event_data(event);
+ /*
+ * The ring buffer is a size of trace_buf_size, if
+ * we loop more than the size, there's something wrong
+ * with the ring buffer.
+ */
+ if (loops++ > trace_buf_size) {
+ printk(KERN_CONT ".. bad ring buffer ");
+ goto failed;
+ }
if (!trace_valid_entry(entry)) {
printk(KERN_CONT ".. invalid entry %d ",
entry->type);