| Message ID | 20230518110727.2106156-4-ryan.roberts@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Encapsulate PTE contents from non-arch code | expand |
On Thu, May 18, 2023 at 12:07:25PM +0100, Ryan Roberts wrote: > The loser of a race to service a pte for a device private entry in the > swap path previously unlocked the ptl, but failed to unmap the pte. This > only affects highmem systems since unmapping a pte is a noop on > non-highmem systems. > > Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device private page") > Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> > Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> > --- > mm/memory.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index f69fbc251198..ed429e20a1bb 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -3728,10 +3728,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > vmf->page = pfn_swap_entry_to_page(entry); > vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, > vmf->address, &vmf->ptl); > - if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { > - spin_unlock(vmf->ptl); > - goto out; > - } > + if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) > + goto unlock; > > /* > * Get a page reference while we know the page can't be > -- > 2.25.1 > >
diff --git a/mm/memory.c b/mm/memory.c index f69fbc251198..ed429e20a1bb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3728,10 +3728,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) vmf->page = pfn_swap_entry_to_page(entry); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); - if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { - spin_unlock(vmf->ptl); - goto out; - } + if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) + goto unlock; /* * Get a page reference while we know the page can't be
The loser of a race to service a pte for a device private entry in the swap path previously unlocked the ptl, but failed to unmap the pte. This only affects highmem systems since unmapping a pte is a noop on non-highmem systems. Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device private page") Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Zi Yan <ziy@nvidia.com> --- mm/memory.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)