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authorRobert Richter <robert.richter@amd.com>2009-01-17 17:13:27 +0100
committerIngo Molnar <mingo@elte.hu>2009-01-17 17:26:39 +0100
commitfdb6a8f4db813b4e50f4e975efe6be12ba5bf460 (patch)
treeffb4cd30eb41639779925f7c81eaba0e95e9261a /drivers/oprofile
parentc903ff837909ccada51243307d4239f86af40179 (diff)
downloadlinux-fdb6a8f4db813b4e50f4e975efe6be12ba5bf460.tar.bz2
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>
Diffstat (limited to 'drivers/oprofile')
-rw-r--r--drivers/oprofile/cpu_buffer.c5
-rw-r--r--drivers/oprofile/cpu_buffer.h7
2 files changed, 12 insertions, 0 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 2e03b6d796d3..e76d715e4342 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -393,16 +393,21 @@ oprofile_write_reserve(struct op_entry *entry, struct pt_regs * const regs,
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 63f81c44846a..272995d20293 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -66,6 +66,13 @@ static inline void op_cpu_buffer_reset(int cpu)
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);