futex: request only one page from get_user_pages()

Yanmin noticed that fault_in_user_writeable() requests 4 pages instead of one. That's the result of blindly trusting Linus' proposal :) I even looked up the prototype to verify the correctness: the argument in question is confusingly enough named "len" while in reality it means number of pages. Pointed-out-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

futex: request only one page from get_user_pages()
Yanmin noticed that fault_in_user_writeable() requests 4 pages instead of one. That's the result of blindly trusting Linus' proposal :) I even looked up the prototype to verify the correctness: the argument in question is confusingly enough named "len" while in reality it means number of pages. Pointed-out-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Thomas Gleixner
1 parent 28d0325ce6
Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff
kernel/futex.c
@@ -299,7 +299,7 @@
 static int fault_in_user_writeable(u32 __user *uaddr)
 {
 	int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
-				 sizeof(*uaddr), 1, 0, NULL, NULL);
+				 1, 1, 0, NULL, NULL);
 	return ret < 0 ? ret : 0;
 }
...	...	@@ -299,7 +299,7 @@
299	299	static int fault_in_user_writeable(u32 __user *uaddr)
300	300	{
301	301	int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
302		- sizeof(*uaddr), 1, 0, NULL, NULL);
	302	+ 1, 1, 0, NULL, NULL);
303	303	return ret < 0 ? ret : 0;
304	304	}
305	305