Re: [PATCH drm-dp 04/10] drm/hisilicon/hibmc: fix the hibmc loaded failed bug

[Yongbang Shi]

From: Baihan Li<libai...@huawei.com>

When hibmc loaded failed, the driver use hibmc_unload to free the
resource, but the mutexes in mode.config are not init, which will
access an NULL pointer.

Fixes: b3df5e65cc03 ("drm/hibmc: Drop drm_vblank_cleanup")
Reported-by:oushixiong1...@163.com
Signed-off-by: Baihan Li<libai...@huawei.com>
---
  drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c 
b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 4cdcc34070ee..ac552c339671 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -319,13 +319,13 @@ static int hibmc_load(struct drm_device *dev)

ret = hibmc_hw_init(priv);

        if (ret)
-               goto err;
+               return ret;

ret = drmm_vram_helper_init(dev, pci_resource_start(pdev, 0),

                                    pci_resource_len(pdev, 0));
        if (ret) {
                drm_err(dev, "Error initializing VRAM MM; %d\n", ret);
-               goto err;
+               return ret;

The mutexes in mode.config are initialized when calling hibmc_kms_init(),
if calling hibmc_kms_init() failed it also need to return.

You may want to look at the following patch:

LKML: oushixiong1025@163 ...: [PATCH] drm/hisilicon: Fix a NULL pointer access when hibmc_load failed <https://lkml.org/lkml/2025/5/20/331>

Reported-by: Shixiong Ou <oushixi...@kylinos.cn>

Thanks and Regards,
Shixiong Ou.

Hi Shixiong,
Thanks for your advice!
Actually, even if the calling of drmm_mode_config_init() failed, these mutexes 
are still initialized,
and it's the same for hibmc_kms_init() failed, so we don't need to change its 
return.

Thanks,
Baihan Li

        }

ret = hibmc_kms_init(priv);