1 files changed, 40 insertions, 10 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 7465f22..c5db9a7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -14,6 +14,7 @@
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/interrupt.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
@@ -381,8 +382,9 @@ found:
 			goto retry;
 		}
 		if (printk_ratelimit())
-			printk(KERN_WARNING "vmap allocation failed: "
-				 "use vmalloc=<size> to increase size.\n");
+			printk(KERN_WARNING
+				"vmap allocation for size %lu failed: "
+				"use vmalloc=<size> to increase size.\n", size);
 		return ERR_PTR(-EBUSY);
 	}
 
@@ -432,6 +434,27 @@ static void unmap_vmap_area(struct vmap_area *va)
 	vunmap_page_range(va->va_start, va->va_end);
 }
 
+static void vmap_debug_free_range(unsigned long start, unsigned long end)
+{
+	/*
+	 * Unmap page tables and force a TLB flush immediately if
+	 * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
+	 * bugs similarly to those in linear kernel virtual address
+	 * space after a page has been freed.
+	 *
+	 * All the lazy freeing logic is still retained, in order to
+	 * minimise intrusiveness of this debugging feature.
+	 *
+	 * This is going to be *slow* (linear kernel virtual address
+	 * debugging doesn't do a broadcast TLB flush so it is a lot
+	 * faster).
+	 */
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	vunmap_page_range(start, end);
+	flush_tlb_kernel_range(start, end);
+#endif
+}
+
 /*
  * lazy_max_pages is the maximum amount of virtual address space we gather up
  * before attempting to purge with a TLB flush.
@@ -472,7 +495,7 @@ static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
 static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
 					int sync, int force_flush)
 {
-	static DEFINE_SPINLOCK(purge_lock);
+	static DEFINE_MUTEX(purge_lock);
 	LIST_HEAD(valist);
 	struct vmap_area *va;
 	int nr = 0;
@@ -483,10 +506,10 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
 	 * the case that isn't actually used at the moment anyway.
 	 */
 	if (!sync && !force_flush) {
-		if (!spin_trylock(&purge_lock))
+		if (!mutex_trylock(&purge_lock))
 			return;
 	} else
-		spin_lock(&purge_lock);
+		mutex_lock(&purge_lock);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(va, &vmap_area_list, list) {
@@ -518,7 +541,7 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
 			__free_vmap_area(va);
 		spin_unlock(&vmap_area_lock);
 	}
-	spin_unlock(&purge_lock);
+	mutex_unlock(&purge_lock);
 }
 
 /*
@@ -912,6 +935,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
 	BUG_ON(addr & (PAGE_SIZE-1));
 
 	debug_check_no_locks_freed(mem, size);
+	vmap_debug_free_range(addr, addr+size);
 
 	if (likely(count <= VMAP_MAX_ALLOC))
 		vb_free(mem, size);
@@ -1128,6 +1152,8 @@ struct vm_struct *remove_vm_area(const void *addr)
 	if (va && va->flags & VM_VM_AREA) {
 		struct vm_struct *vm = va->private;
 		struct vm_struct *tmp, **p;
+
+		vmap_debug_free_range(va->va_start, va->va_end);
 		free_unmap_vmap_area(va);
 		vm->size -= PAGE_SIZE;
 
@@ -1375,7 +1401,8 @@ void *vmalloc_user(unsigned long size)
 	struct vm_struct *area;
 	void *ret;
 
-	ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
+	ret = __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+			     PAGE_KERNEL, -1, __builtin_return_address(0));
 	if (ret) {
 		area = find_vm_area(ret);
 		area->flags |= VM_USERMAP;
@@ -1420,7 +1447,8 @@ EXPORT_SYMBOL(vmalloc_node);
 
 void *vmalloc_exec(unsigned long size)
 {
-	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
+	return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
+			      -1, __builtin_return_address(0));
 }
 
 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
@@ -1440,7 +1468,8 @@ void *vmalloc_exec(unsigned long size)
  */
 void *vmalloc_32(unsigned long size)
 {
-	return __vmalloc(size, GFP_VMALLOC32, PAGE_KERNEL);
+	return __vmalloc_node(size, GFP_VMALLOC32, PAGE_KERNEL,
+			      -1, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(vmalloc_32);
 
@@ -1456,7 +1485,8 @@ void *vmalloc_32_user(unsigned long size)
 	struct vm_struct *area;
 	void *ret;
 
-	ret = __vmalloc(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL);
+	ret = __vmalloc_node(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
+			     -1, __builtin_return_address(0));
 	if (ret) {
 		area = find_vm_area(ret);
 		area->flags |= VM_USERMAP;