CVE-2024-50156

In the Linux kernel, the following vulnerability has been resolved:

drm/msm: Avoid NULL dereference in msmdispstateprintregs()

If the allocation in msmdispstatedumpregs() failed then block->state can be NULL. The msmdispstateprintregs() function does have code to try to handle it with:

if (*reg) dump_addr = *reg;

...but since "dump_addr" is initialized to NULL the above is actually a noop. The code then goes on to dereference dump_addr.

Make the function print "Registers not stored" when it sees a NULL to solve this. Since we're touching the code, fix msmdispstateprintregs() not to pointlessly take a double-pointer and properly mark the pointer as const.

Patchwork: https://patchwork.freedesktop.org/patch/619657/