[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Sun, 16 Oct 2016 05:18:03 +0200
From: Mike Galbraith <umgwanakikbuti@...il.com>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
linux-rt-users <linux-rt-users@...r.kernel.org>,
Steven Rostedt <rostedt@...dmis.org>
Subject: [patch ]mm/zs_malloc: Fix bit spinlock replacement
Do not alter HANDLE_SIZE, memory corruption ensues. The handle is
a pointer, allocate space for the struct it points to and align it
ZS_ALIGN. Also, when accessing the struct, mask HANDLE_PIN_BIT.
Signed-off-by: Mike Galbraith <umgwanakikbuti@...il.com>
---
mm/zsmalloc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -71,6 +71,8 @@
#define ZS_MAX_ZSPAGE_ORDER 2
#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
+#define ZS_HANDLE_SIZE (sizeof(unsigned long))
+
#ifdef CONFIG_PREEMPT_RT_BASE
struct zsmalloc_handle {
@@ -78,11 +80,11 @@ struct zsmalloc_handle {
struct mutex lock;
};
-#define ZS_HANDLE_SIZE (sizeof(struct zsmalloc_handle))
+#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
#else
-#define ZS_HANDLE_SIZE (sizeof(unsigned long))
+#define ZS_HANDLE_ALLOC_SIZE ZS_HANDLE_SIZE
#endif
/*
@@ -339,8 +341,9 @@ static void SetZsPageMovable(struct zs_p
static int create_cache(struct zs_pool *pool)
{
- pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
- 0, 0, NULL);
+ pool->handle_cachep = kmem_cache_create("zs_handle",
+ ZS_HANDLE_ALLOC_SIZE,
+ ZS_ALIGN, 0, NULL);
if (!pool->handle_cachep)
return 1;
@@ -380,7 +383,7 @@ static unsigned long cache_alloc_handle(
#ifdef CONFIG_PREEMPT_RT_BASE
static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle)
{
- return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1));
+ return (void *)(handle & ~BIT(HANDLE_PIN_BIT));
}
#endif
Powered by blists - more mailing lists