On Thu, Feb 1, 2018 at 4:02 PM, Robin Murphy [off-list ref] wrote:

On 01/02/18 11:00, Himanshu Jha wrote:

quoted

In scpsys_probe function, return value of of_match_device function which
returns null is dereferenced without checking. Therefore, add a check for
potential null dereference.

Detected by CoverityScan, CID#1424087 "Dereference null return value"

Fixes: commit 53fddb1a66dd ("soc: mediatek: reduce code duplication of
scpsys_probe across all SoCs")
Signed-off-by: Himanshu Jha <redacted>
---
  drivers/soc/mediatek/mtk-scpsys.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/drivers/soc/mediatek/mtk-scpsys.c

b/drivers/soc/mediatek/mtk-scpsys.c
index 435ce5e..6e7f196 100644

--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c

@@ -981,6 +981,9 @@ static int scpsys_probe(struct platform_device *pdev)
        int i, ret;
        match = of_match_device(of_scpsys_match_tbl, &pdev->dev);
+       if (!match)
+               return -EINVAL;
+
        soc = (const struct scp_soc_data *)match->data;

You could of course replace the whole sequence with an
of_device_get_match_data() call, which happens to be inherently safe against
the no-match case even when that *is* impossible by design.

+1

quoted

        scp = init_scp(pdev, soc->domains, soc->num_domains, &soc->regs,

... followed by the static analyser gang complaining we may dereference
NULL pointer soc...

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds