On Fri, Jul 4, 2014 at 7:07 PM, Emil Goode <emilgoode@xxxxxxxxx> wrote:
> We check that the struct vm_area_struct pointer vma is NULL and
> then dereference it. The intent must have been to check that
> vma is not NULL before we dereference it in the next condition.
Actually if it is NULL, then it will short-cut and won't dereference
it (because !vma is true it can never become false again), so the
condition would be fine previously.
But, looking at the code a few lines into branch:
if (!vma || cpu_context(cpu, vma->vm_mm) != 0) {
unsigned long flags;
int oldpid, newpid, idx;
#ifdef DEBUG_TLB
printk("[tlbpage<%lu,0x%08lx>]", cpu_context(cpu,
vma->vm_mm), page);
#endif
newpid = cpu_context(cpu, vma->vm_mm) & ASID_MASK;
it will be then dereferenced here, so the change is actually sensible,
even if the description isn't quite spot-on where it breaks.
Jonas
