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-rw-r--r--drivers/misc/lkdtm/refcount.c8
-rw-r--r--drivers/misc/lkdtm/usercopy.c17
2 files changed, 14 insertions, 11 deletions
diff --git a/drivers/misc/lkdtm/refcount.c b/drivers/misc/lkdtm/refcount.c
index 0a146b32da13..abf3b7c1f686 100644
--- a/drivers/misc/lkdtm/refcount.c
+++ b/drivers/misc/lkdtm/refcount.c
@@ -6,14 +6,6 @@
#include "lkdtm.h"
#include <linux/refcount.h>
-#ifdef CONFIG_REFCOUNT_FULL
-#define REFCOUNT_MAX (UINT_MAX - 1)
-#define REFCOUNT_SATURATED UINT_MAX
-#else
-#define REFCOUNT_MAX INT_MAX
-#define REFCOUNT_SATURATED (INT_MIN / 2)
-#endif
-
static void overflow_check(refcount_t *ref)
{
switch (refcount_read(ref)) {
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index e172719dd86d..4617c63b1026 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -30,12 +30,12 @@ static const unsigned char test_text[] = "This is a test.\n";
*/
static noinline unsigned char *trick_compiler(unsigned char *stack)
{
- return stack + 0;
+ return stack + unconst;
}
static noinline unsigned char *do_usercopy_stack_callee(int value)
{
- unsigned char buf[32];
+ unsigned char buf[128];
int i;
/* Exercise stack to avoid everything living in registers. */
@@ -43,7 +43,12 @@ static noinline unsigned char *do_usercopy_stack_callee(int value)
buf[i] = value & 0xff;
}
- return trick_compiler(buf);
+ /*
+ * Put the target buffer in the middle of stack allocation
+ * so that we don't step on future stack users regardless
+ * of stack growth direction.
+ */
+ return trick_compiler(&buf[(128/2)-32]);
}
static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
@@ -66,6 +71,12 @@ static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
bad_stack -= sizeof(unsigned long);
}
+#ifdef ARCH_HAS_CURRENT_STACK_POINTER
+ pr_info("stack : %px\n", (void *)current_stack_pointer);
+#endif
+ pr_info("good_stack: %px-%px\n", good_stack, good_stack + sizeof(good_stack));
+ pr_info("bad_stack : %px-%px\n", bad_stack, bad_stack + sizeof(good_stack));
+
user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);