From: yangshiguang yangshiguang@xiaomi.com
Check in debugfs_read_file_str() if the string pointer is NULL.
When creating a node using debugfs_create_str(), the string parameter value can be NULL to indicate empty/unused/ignored. However, reading this node using debugfs_read_file_str() will cause a kernel panic. This should not be fatal, so return an invalid error.
Signed-off-by: yangshiguang yangshiguang@xiaomi.com Fixes: 9af0440ec86e ("debugfs: Implement debugfs_create_str()") Cc: stable@vger.kernel.org --- fs/debugfs/file.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 3ec3324c2060..a22ff0ceb230 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1026,6 +1026,9 @@ ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf, return ret;
str = *(char **)file->private_data; + if (!str) + return -EINVAL; + len = strlen(str) + 1; copy = kmalloc(len, GFP_KERNEL); if (!copy) {