1 files changed, 9 insertions, 5 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index baa09601a64e..66e5a0516f23 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -483,29 +483,33 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
                 unsigned long addr = regs->ARM_r2;
                 struct mm_struct *mm = current->mm;
                 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
+                spinlock_t *ptl;
 
                 regs->ARM_cpsr &= ~PSR_C_BIT;
-                spin_lock(&mm->page_table_lock);
+                down_read(&mm->mmap_sem);
                 pgd = pgd_offset(mm, addr);
                 if (!pgd_present(*pgd))
                         goto bad_access;
                 pmd = pmd_offset(pgd, addr);
                 if (!pmd_present(*pmd))
                         goto bad_access;
-                pte = pte_offset_map(pmd, addr);
-                if (!pte_present(*pte) || !pte_write(*pte))
+                pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+                if (!pte_present(*pte) || !pte_write(*pte)) {
+                        pte_unmap_unlock(pte, ptl);
                         goto bad_access;
+                }
                 val = *(unsigned long *)addr;
                 val -= regs->ARM_r0;
                 if (val == 0) {
                         *(unsigned long *)addr = regs->ARM_r1;
                         regs->ARM_cpsr |= PSR_C_BIT;
                 }
-                spin_unlock(&mm->page_table_lock);
+                pte_unmap_unlock(pte, ptl);
+                up_read(&mm->mmap_sem);
                 return val;
 
                 bad_access:
-                spin_unlock(&mm->page_table_lock);
+                up_read(&mm->mmap_sem);
                 /* simulate a write access fault */
                 do_DataAbort(addr, 15 + (1 << 11), regs);
                 return -1;