ext4: fix a double free in ext4_register_li_request
In ext4_register_li_request, we malloc a ext4_li_request and
inserts it into ext4_li_info->li_request_list. In case of any
error later, we free it in the end. But if we have some error
in ext4_run_lazyinit_thread, the whole li_request_list will be
dropped and freed in it. So we will double free this ext4_li_request.
This patch just sets elr to NULL after it is inserted to the list
so that the latter kfree won't double free it.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 35ff9fe..35bd020 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2975,6 +2975,12 @@
mutex_unlock(&ext4_li_info->li_list_mtx);
sbi->s_li_request = elr;
+ /*
+ * set elr to NULL here since it has been inserted to
+ * the request_list and the removal and free of it is
+ * handled by ext4_clear_request_list from now on.
+ */
+ elr = NULL;
if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
ret = ext4_run_lazyinit_thread();