When using remap_pfn_range() from a fault handler, we are exposed to
races between concurrent faults. Rather than hitting a BUG, report the
error back to the caller, like vm_insert_pfn().
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---
mm/memory.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 037b812a9531..6603a9e6a731 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2306,19 +2306,23 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
{
pte_t *pte;
spinlock_t *ptl;
+ int ret = 0;
pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
arch_enter_lazy_mmu_mode();
do {
- BUG_ON(!pte_none(*pte));
+ if (!pte_none(*pte)) {
+ ret = -EBUSY;
+ break;
+ }
set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
arch_leave_lazy_mmu_mode();
pte_unmap_unlock(pte - 1, ptl);
- return 0;
+ return ret;
}
static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
--
2.0.0
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
