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-rw-r--r--mm/vmalloc.c50
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;
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