On Sat, Mar 21, 2020 at 09:38:04AM -0300, Jason Gunthorpe wrote:
> > I don't think there is any specific protection. Let me see if we
> > can throw in a get_dev_pagemap here
>
> The page tables are RCU protected right? could we do something like
>
> if (is_device_private_entry()) {
>rcu
On Sat, Mar 21, 2020 at 09:22:36AM +0100, Christoph Hellwig wrote:
> On Fri, Mar 20, 2020 at 10:41:09AM -0300, Jason Gunthorpe wrote:
> > Thinking about this some more, does the locking work out here?
> >
> > hmm_range_fault() runs with mmap_sem in read, and does not lock any of
> > the page table
On Fri, Mar 20, 2020 at 10:41:09AM -0300, Jason Gunthorpe wrote:
> Thinking about this some more, does the locking work out here?
>
> hmm_range_fault() runs with mmap_sem in read, and does not lock any of
> the page table levels.
>
> So it relies on accessing stale pte data being safe, and here w
On Mon, Mar 16, 2020 at 08:32:16PM +0100, Christoph Hellwig wrote:
> diff --git a/mm/hmm.c b/mm/hmm.c
> index cfad65f6a67b..b75b3750e03d 100644
> +++ b/mm/hmm.c
> @@ -216,6 +216,14 @@ int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned
> long addr,
> unsigned long end, uint64_t *pf
On 3/16/20 12:32 PM, Christoph Hellwig wrote:
Hmm range fault will succeed for any kind of device private memory,
even if it doesn't belong to the calling entity. While nouveau
has some crude checks for that, they are broken because they assume
nouveau is the only user of device private memory
On Mon, Mar 16, 2020 at 08:32:16PM +0100, Christoph Hellwig wrote:
> Hmm range fault will succeed for any kind of device private memory,
> even if it doesn't belong to the calling entity. While nouveau
> has some crude checks for that, they are broken because they assume
> nouveau is the only user
Hmm range fault will succeed for any kind of device private memory,
even if it doesn't belong to the calling entity. While nouveau
has some crude checks for that, they are broken because they assume
nouveau is the only user of device private memory. Fix this by
passing in an expected pgmap owner
