dpll: Add a check before kfree() to match the existing check before k…

…memdup()

When src->freq_supported is not NULL but src->freq_supported_num is 0,
dst->freq_supported is equal to src->freq_supported.
In this case, if the subsequent kstrdup() fails, src->freq_supported may
be freed without being set to NULL, potentially leading to a
use-after-free or double-free error.

Fixes: 830ead5 ("dpll: fix pin dump crash for rebound module")
Cc: <stable@vger.kernel.org> # v6.8+
Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
Signed-off-by: NipaLocal <nipa@local>

drivers/dpll/dpll_core.c

@@ -475,7 +475,8 @@ static int dpll_pin_prop_dup(const struct dpll_pin_properties *src,
 err_panel_label:
 	kfree(dst->board_label);
 err_board_label:
-	kfree(dst->freq_supported);
+	if (src->freq_supported_num)
+		kfree(dst->freq_supported);
 	return -ENOMEM;
 }