On 11/18/22 04:53, Zeng Heng wrote:
> In of_changeset_action(), we have called of_node_get() to increase
> refcount of a node.
>
> Therefore, when tchild (duplicated by __of_node_dup()) is done,
> of_node_put() needs to call and release the device_node.
>
> Otherwise, there are some memory leak reported about the node:
>
> unreferenced object 0xffff88810cd1e800 (size 256):
> backtrace:
> kmalloc_trace
> __of_node_dup
> add_changeset_node (inlined)
> build_changeset_next_level
>
> unreferenced object 0xffff888113721240 (size 16):
> backtrace:
> __kmalloc_node_track_caller
> kstrdup
> __of_node_dup
> add_changeset_node (inlined)
> build_changeset_next_level
>
> unreferenced object 0xffff88810a38d400 (size 128):
> backtrace:
> kmalloc_trace
> __of_prop_dup
> add_changeset_property
> build_changeset_next_level
>
> Fixes: 7518b5890d8a ("of/overlay: Introduce DT overlay support")
> Signed-off-by: Zeng Heng <zengheng4@xxxxxxxxxx>
> ---
> drivers/of/overlay.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index bd8ff4df723d..a5189a0ec0a3 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -436,8 +436,10 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
> of_node_set_flag(tchild, OF_OVERLAY);
>
> ret = of_changeset_attach_node(&ovcs->cset, tchild);
> - if (ret)
> + if (ret) {
> + of_node_put(tchild);
> return ret;
> + }
By visual inspection of the code (Linux 6.1-rc1), this does not appear to be
correct. For the only case where of_changeset_action(),
called by of_changeset_attach_node(), returns an error, of_node_get() has not
yet occurred on tchild.
>
> target_child.np = tchild;
> target_child.in_livetree = false;
For which version of Linux were the memory leaks detected? Were any additional
patches applied?
-Frank
