x86, pat: Fix memory leak in free_memtype

Reserve_memtype will allocate memory for new memtype, but
in free_memtype, after the memtype erased from rbtree, the
memory is not freed.

Changes since V1:
	make rbt_memtype_erase return erased memtype so that
	it can be freed in free_memtype.

[ hpa: not for -stable: 2.6.34 and earlier not affected ]

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1274838670-8731-1-git-send-email-dfeng@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Jack Steiner <steiner@sgi.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

3 files changed, 14 insertions, 9 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index bbe5502ee1cb..acc15b23b743 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -336,6 +336,7 @@ int free_memtype(u64 start, u64 end)
 {
         int err = -EINVAL;
         int is_range_ram;
+        struct memtype *entry;
 
         if (!pat_enabled)
                 return 0;
@@ -355,17 +356,20 @@ int free_memtype(u64 start, u64 end)
         }
 
         spin_lock(&memtype_lock);
-        err = rbt_memtype_erase(start, end);
+        entry = rbt_memtype_erase(start, end);
         spin_unlock(&memtype_lock);
 
-        if (err) {
+        if (!entry) {
                 printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
                         current->comm, current->pid, start, end);
+                return -EINVAL;
         }
 
+        kfree(entry);
+
         dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
 
-        return err;
+        return 0;
 }
 
 
diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h
index 4f39eefa3e61..77e5ba153fac 100644
--- a/arch/x86/mm/pat_internal.h
+++ b/arch/x86/mm/pat_internal.h
@@ -28,15 +28,15 @@ static inline char *cattr_name(unsigned long flags)
 #ifdef CONFIG_X86_PAT
 extern int rbt_memtype_check_insert(struct memtype *new,
                                         unsigned long *new_type);
-extern int rbt_memtype_erase(u64 start, u64 end);
+extern struct memtype *rbt_memtype_erase(u64 start, u64 end);
 extern struct memtype *rbt_memtype_lookup(u64 addr);
 extern int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos);
 #else
 static inline int rbt_memtype_check_insert(struct memtype *new,
                                         unsigned long *new_type)
 { return 0; }
-static inline int rbt_memtype_erase(u64 start, u64 end)
-{ return 0; }
+static inline struct memtype *rbt_memtype_erase(u64 start, u64 end)
+{ return NULL; }
 static inline struct memtype *rbt_memtype_lookup(u64 addr)
 { return NULL; }
 static inline int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 07de4cb8cc30..f537087bb740 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -231,16 +231,17 @@ int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
         return err;
 }
 
-int rbt_memtype_erase(u64 start, u64 end)
+struct memtype *rbt_memtype_erase(u64 start, u64 end)
 {
         struct memtype *data;
 
         data = memtype_rb_exact_match(&memtype_rbroot, start, end);
         if (!data)
-                return -EINVAL;
+                goto out;
 
         rb_erase(&data->rb, &memtype_rbroot);
-        return 0;
+out:
+        return data;
 }
 
 struct memtype *rbt_memtype_lookup(u64 addr)