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 <[email protected]> Cc: Andrew Morton <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Cyrill Gorcunov <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: [email protected] --- 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 [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
