Messages in this thread | | | From | Andy Lutomirski <> | Date | Tue, 10 May 2016 14:11:41 -0700 | Subject | Re: Getting rid of dynamic TASK_SIZE (on x86, at least) |
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On Tue, May 10, 2016 at 10:49 AM, Cyrill Gorcunov <gorcunov@gmail.com> wrote: > On Tue, May 10, 2016 at 10:26:05AM -0700, Andy Lutomirski wrote: > ... >> >> >> >> It's annoying and ugly. It also makes the idea of doing 32-bit CRIU >> >> restore by starting in 64-bit mode and switching to 32-bit more >> >> complicated because it requires switching TASK_SIZE. >> > >> > Well, you know I'm not sure it's that annoying. It serves as it should >> > for task limit. Sure we can add one more parameter into get-unmapped-addr >> > but same time the task-size will be present in say page faulting code >> > (the helper might be renamed but it will be here still). >> >> Why should the page faulting code care at all what type of task it is? >> If there's a vma there, fault it in. If there isn't, then don't. > > __bad_area_nosemaphore > ... > /* Kernel addresses are always protection faults: */ > if (address >= TASK_SIZE) > error_code |= PF_PROT; > > For sure page faulting must consider what kind of fault is it. > Or we gonna drop such code at all?
That code was bogus. (Well, it was correct unless user code had a way to create a funny high mapping in an otherwise 32-bit task, but it still should have been TASK_SIZE_MAX.) Fix sent.
--Andy
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