On Fri, Apr 10, 2020 at 2:32 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> In fixup_user_fault(), it is possible that unlocked is NULL,
> so we should test unlocked before using it.
This seems wrong.
> For example, in arch/arc/kernel/process.c, NULL is passed
> to fixup_user_fault().
>
> ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr,
> FAULT_FLAG_WRITE, NULL);
Yes, but it doesn't set FAULT_FLAG_ALLOW_RETRY, exactly _because_
'unlocked' is NULL.
Basically, retry is fundamentally tied to that "unlocked" flag. You
can't ask for retry without also saying "please tell me if you
unlocked the mmap_sem during the retry". So the two go hand in hand
there.
So I think this is just coverity not understanding the rules.
Or maybe I'm the one missing something. Did you actually see a problem?
Linus
