RaspberryPi4 Panic in net_ns_init()

[Maxime Ripard]

On Wed, Aug 31, 2022 at 04:42:05PM +0200, Maxime Ripard wrote:
> Sorry for the fairly broad list of recipients, I'm not entirely sure
> where the issue lies exactly, and it seems like multiple areas are
> involved.
> 
> Martin reported me an issue discovered with the VC4 DRM driver that
> would prevent the RaspberryPi4 from booting entirely. At boot, and
> apparently before the console initialization, the board would just die.
> 
> It first appeared when both DYNAMIC_DEBUG and DRM_VC4 were built-in. We
> started to look into what configuration would trigger it.
> 
> It looks like a good reproducer is:
> 
> ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make -j18 defconfig mod2yesconfig
> ./scripts/config -e CONFIG_DYNAMIC_DEBUG
> ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make -j18 olddefconfig

Interestingly, this was making the kernel Image cross the 64MB boundary.
I've compiled the same configuration but with -Os, and then tried to
boot the failing configuration with U-Boot instead of the RaspberryPi
firmware, and both of them worked. I guess that leaves us with a
bootloader bug, and nothing related to Linux after all.

Sorry for the noise,
Maxime