oprofile: fix uninitialized use of struct op_entry
Impact: fix crash
In case of losing samples struct op_entry could have been used
uninitialized causing e.g. a wrong preemption count or NULL pointer
access. This patch fixes this.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 2e03b6d..e76d715 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -393,16 +393,21 @@
return;
fail:
+ entry->event = NULL;
cpu_buf->sample_lost_overflow++;
}
int oprofile_add_data(struct op_entry *entry, unsigned long val)
{
+ if (!entry->event)
+ return 0;
return op_cpu_buffer_add_data(entry, val);
}
int oprofile_write_commit(struct op_entry *entry)
{
+ if (!entry->event)
+ return -EINVAL;
return op_cpu_buffer_write_commit(entry);
}
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 63f81c4..272995d 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -66,6 +66,13 @@
cpu_buf->last_task = NULL;
}
+/*
+ * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
+ * called only if op_cpu_buffer_write_reserve() did not return NULL or
+ * entry->event != NULL, otherwise entry->size or entry->event will be
+ * used uninitialized.
+ */
+
struct op_sample
*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
int op_cpu_buffer_write_commit(struct op_entry *entry);
