Now disabling kmemleak is an irreversible operation, but sometimes
we may need to re-enable kmemleak at runtime. So add a knob to enable
kmemleak at runtime:
echo on > /sys/kernel/debug/kmemleak
Signed-off-by: Jianguo Wu <wujian...@huawei.com>
---
Documentation/kmemleak.txt | 3 ++-
mm/kmemleak.c | 37 +++++++++++++++++++++++++++++++++----
2 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
index b6e3973..8ec56ad 100644
--- a/Documentation/kmemleak.txt
+++ b/Documentation/kmemleak.txt
@@ -44,7 +44,8 @@ objects to be reported as orphan.
Memory scanning parameters can be modified at run-time by writing to the
/sys/kernel/debug/kmemleak file. The following parameters are supported:
- off - disable kmemleak (irreversible)
+ off - disable kmemleak
+ on - enable kmemleak
stack=on - enable the task stacks scanning (default)
stack=off - disable the tasks stacks scanning
scan=on - start the automatic memory scanning thread (default)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 31f01c5..02f292c 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -260,6 +260,7 @@ static struct early_log
static int crt_early_log __initdata;
static void kmemleak_disable(void);
+static void kmemleak_enable(void);
/*
* Print a warning and dump the stack trace.
@@ -1616,9 +1617,6 @@ static ssize_t kmemleak_write(struct file *file, const
char __user *user_buf,
int buf_size;
int ret;
- if (!atomic_read(&kmemleak_enabled))
- return -EBUSY;
-
buf_size = min(size, (sizeof(buf) - 1));
if (strncpy_from_user(buf, user_buf, buf_size) < 0)
return -EFAULT;
@@ -1628,6 +1626,19 @@ static ssize_t kmemleak_write(struct file *file, const
char __user *user_buf,
if (ret < 0)
return ret;
+ if (strncmp(buf, "on", 2) == 0) {
+ if (atomic_read(&kmemleak_enabled))
+ ret = -EBUSY;
+ else
+ kmemleak_enable();
+ goto out;
+ }
+
+ if (!atomic_read(&kmemleak_enabled)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
if (strncmp(buf, "off", 3) == 0)
kmemleak_disable();
else if (strncmp(buf, "stack=on", 8) == 0)
@@ -1703,7 +1714,7 @@ static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
/*
* Disable kmemleak. No memory allocation/freeing will be traced once this
- * function is called. Disabling kmemleak is an irreversible operation.
+ * function is called.
*/
static void kmemleak_disable(void)
{
@@ -1721,6 +1732,24 @@ static void kmemleak_disable(void)
pr_info("Kernel memory leak detector disabled\n");
}
+static void kmemleak_enable(void)
+{
+ struct kmemleak_object *object;
+
+ /* free the kmemleak internal objects the previous thread scanned */
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list)
+ delete_object_full(object->pointer);
+ rcu_read_unlock();
+
+ atomic_set(&kmemleak_enabled, 1);
+ atomic_set(&kmemleak_error, 0);
+
+ start_scan_thread();
+
+ pr_info("Kernel memory leak detector enabled\n");
+}
+
/*
* Allow boot-time kmemleak disabling (enabled by default).
*/
--
1.7.7
--
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