From 08612fc14b3819ed6f2e0f33e0a532c82ca8f647 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Thu, 29 Sep 2011 11:50:07 +0100 Subject: [PATCH] kmemleak: Report previously found leaks even after an error If an error fatal to kmemleak (like memory allocation failure) happens, kmemleak disables itself but it also removes the access to any previously found memory leaks. This patch allows read-only access to the kmemleak debugfs interface but disables any other action. Reported-by: Nick Bowler Signed-off-by: Catalin Marinas --- mm/kmemleak.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e8c905b70aa8..b4f4e6021c1b 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1473,9 +1473,6 @@ static const struct seq_operations kmemleak_seq_ops = { static int kmemleak_open(struct inode *inode, struct file *file) { - if (!atomic_read(&kmemleak_enabled)) - return -EBUSY; - return seq_open(file, &kmemleak_seq_ops); } @@ -1549,6 +1546,9 @@ 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; @@ -1608,20 +1608,24 @@ static const struct file_operations kmemleak_fops = { }; /* - * Perform the freeing of the kmemleak internal objects after waiting for any - * current memory scan to complete. + * Stop the memory scanning thread and free the kmemleak internal objects if + * no previous scan thread (otherwise, kmemleak may still have some useful + * information on memory leaks). */ static void kmemleak_do_cleanup(struct work_struct *work) { struct kmemleak_object *object; + bool cleanup = scan_thread == NULL; mutex_lock(&scan_mutex); stop_scan_thread(); - rcu_read_lock(); - list_for_each_entry_rcu(object, &object_list, object_list) - delete_object_full(object->pointer); - rcu_read_unlock(); + if (cleanup) { + rcu_read_lock(); + list_for_each_entry_rcu(object, &object_list, object_list) + delete_object_full(object->pointer); + rcu_read_unlock(); + } mutex_unlock(&scan_mutex); } -- 2.39.5