From: Anirudh Rayabharam <mail@anirudhrb.com> commit 02625c965239b71869326dd0461615f27307ecb3 upstream. The return value of hga_card_detect() is not properly handled causing the probe to succeed even though hga_card_detect() failed. Since probe succeeds, hgafb_open() can be called which will end up operating on an unmapped hga_vram. This results in an out-of-bounds access as reported by kernel test robot [1]. To fix this, correctly detect failure of hga_card_detect() by checking for a non-zero error code. [1]: https://lore.kernel.org/lkml/20210516150019.GB25903@xsang-OptiPlex-9020/ Fixes: dc13cac4862c ("video: hgafb: fix potential NULL pointer dereference") Cc: stable <stable@vger.kernel.org> Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com> Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Link: https://lore.kernel.org/r/20210516192714.25823-1-mail@anirudhrb.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/video/fbdev/hgafb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c index b2b9961961328..03c0b1b8747b9 100644 --- a/drivers/video/fbdev/hgafb.c +++ b/drivers/video/fbdev/hgafb.c @@ -558,7 +558,7 @@ static int hgafb_probe(struct platform_device *pdev) int ret; ret = hga_card_detect(); - if (!ret) + if (ret) return ret; printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", -- 2.25.1