This patch addresses a use-after-free (UAF) vulnerability in the
sys_mount. The issue occurred due to improper handling of memory
deallocation, which could lead to crashes or undefined behavior on user
request of mounting.
Changes made:
- Moved the `rt_free(copy_source)` function call to occur after the necessary
operations are completed, preventing premature deallocation of memory.
Signed-off-by: Shell <smokewood@qq.com>