ASoC: wm_adsp: Fix theoretical NULL pointer for alg_region

Fix potential NULL pointer dereference for alg_region in
wm_adsp_buffer_parse_legacy. In practice this can never happen as
loading the firmware should have failed at the wm_adsp2_setup_algs
stage, however probably better for the code to be robust against
future changes and this is more helpful for static analysis.

Signed-off-by: Li Xu <li.xu@cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20191001130911.19238-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index ae28d99..85396d9 100644 (file)
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -3697,11 +3697,16 @@ static int wm_adsp_buffer_parse_legacy(struct wm_adsp *dsp)
        u32 xmalg, addr, magic;
        int i, ret;
 
+       alg_region = wm_adsp_find_alg_region(dsp, WMFW_ADSP2_XM, dsp->fw_id);
+       if (!alg_region) {
+               adsp_err(dsp, "No algorithm region found\n");
+               return -EINVAL;
+       }
+
        buf = wm_adsp_buffer_alloc(dsp);
        if (!buf)
                return -ENOMEM;
 
-       alg_region = wm_adsp_find_alg_region(dsp, WMFW_ADSP2_XM, dsp->fw_id);
        xmalg = dsp->ops->sys_config_size / sizeof(__be32);
 
        addr = alg_region->base + xmalg + ALG_XM_FIELD(magic);