Hi Robert,

On 11.08.2021 15:42, Robert Foss wrote:

On Wed, 11 Aug 2021 at 11:41, Robert Foss [off-list ref] wrote:

quoted

Hey Marek,

Thanks for testing this.

On Wed, 11 Aug 2021 at 09:48, Marek Szyprowski [off-list ref] wrote:

quoted

On 10.08.2021 12:33, Robert Foss wrote:

quoted

vfe->ops->hw_version(vfe) being called before vfe->base has been assigned
is incorrect and causes crashes.

Fixes: b10b5334528a9 ("media: camss: vfe: Don't read hardware version needlessly")

Reported-by: Linux Kernel Functional Testing <redacted>
Signed-off-by: Robert Foss <redacted>

With this patch applied on top of linux next-20210810 instead of the
NULL pointer dereference I get following error on DragonBoard410c while
loading kernel modules:

[   18.480608] qcom-venus 1d00000.video-codec: Adding to iommu group 1
[   18.536167] qcom-camss 1b0ac00.camss: Adding to iommu group 2
[   18.600373] Internal error: synchronous external abort: 96000010 [#1]
PREEMPT SMP

After testing this patch + linux-next[1] I'm not able to replicate the
'Internal error' above on the db410c. And I don't think it is related
to this patch.

Are you seeing the same error on [1]? And are you seeing it before the
b10b5334528a9 ("media: camss: vfe: Don't read hardware version
needlessly") patch?

I've checked once again on your branch. Yes, it is fully reproducible on 
my DragonBoard410c. On your branch I get the above synchronous external 
abort, while without your last patch I get Null ptr dereference.

Are you sure you have deployed the kernel modules for doing the test? 
This issue happens when udev triggers loading kernel modules for the 
detected hardware.

Here is the kernel configuration used for my tests on ARM64 based board:

# make ARCH=arm64 defconfig && ./scripts/config --set-val 
CMA_SIZE_MBYTES 96 -e PROVE_LOCKING -e DEBUG_ATOMIC_SLEEP -e PM_DEBUG -e 
PM_ADVANCED_DEBUG -d ARCH_SUNXI -d ARCH_ALPINE -d DRM_NOUVEAU -d 
ARCH_BCM_IPROC -d ARCH_BERLIN -d ARCH_BRCMSTB -d ARCH_LAYERSCAPE -d 
ARCH_LG1K -d ARCH_HISI -d ARCH_MEDIATEK -d ARCH_MVEBU -d ARCH_ROCKCHIP 
-d ARCH_SEATTLE -d ARCH_SYNQUACER -d ARCH_RENESAS -d ARCH_STRATIX10 -d 
ARCH_TEGRA -d ARCH_SPRD -d ARCH_THUNDER -d ARCH_THUNDER2 -d 
ARCH_UNIPHIER -d ARCH_XGENE -d ARCH_ZX -d ARCH_ZYNQMP -d HIBERNATION -d 
CLK_SUNXI -e BLK_DEV_RAM --set-val BLK_DEV_RAM_COUNT 4 --set-val 
BLK_DEV_RAM_SIZE 65536 -d CONFIG_EFI -d CONFIG_TEE

Comparing to the arm64's defconfig, I've enabled some debugging options 
and disabled some unused boards.

Best regards

-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland