patch-2.4.22 linux-2.4.22/arch/ia64/mm/fault.c

• Lines: 60
• Date: 2003-08-25 04:44:39.000000000 -0700
• Orig file: linux-2.4.21/arch/ia64/mm/fault.c
• Orig date: 2003-06-13 07:51:29.000000000 -0700

diff -urN linux-2.4.21/arch/ia64/mm/fault.c linux-2.4.22/arch/ia64/mm/fault.c
@@ -43,6 +43,33 @@
 	return 0;
 }
 
+/*
+ * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
+ * (inside region 5, on ia64) and that page is present.
+ */
+static int
+mapped_kernel_page_is_present (unsigned long address)
+{
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *ptep, pte;
+
+	pgd = pgd_offset_k(address);
+	if (pgd_none(*pgd) || pgd_bad(*pgd))
+		return 0;
+
+	pmd = pmd_offset(pgd,address);
+	if (pmd_none(*pmd) || pmd_bad(*pmd))
+		return 0;
+
+	ptep = pte_offset(pmd, address);
+	if (!ptep)
+		return 0;
+
+	pte = *ptep;
+	return pte_present(pte);
+}
+
 void
 ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
 {
@@ -183,6 +210,16 @@
 		return;
 
 	/*
+	 * Since we have no vma's for region 5, we might get here even if the address is
+	 * valid, due to the VHPT walker inserting a non present translation that becomes
+	 * stale. If that happens, the non present fault handler already purged the stale
+	 * translation, which fixed the problem. So, we check to see if the translation is
+	 * valid, and return if it is.
+	 */
+	if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
+		return;
+
+	/*
 	 * Oops. The kernel tried to access some bad page. We'll have to terminate things
 	 * with extreme prejudice.
 	 */
@@ -204,7 +241,7 @@
 		goto survive;
 	}
 	up_read(&mm->mmap_sem);
-	printk("VM: killing process %s\n", current->comm);
+	printk(KERN_CRIT "VM: killing process %s\n", current->comm);
 	if (user_mode(regs))
 		do_exit(SIGKILL);
 	goto no_context;