[PATCH] Pass correct task to get_user_pages in ptrace

From: Andi Kleen <ak@suse.de>

ptrace/access_process_vm was passing current to get_user_pages as task, but
it should have been clearly the child task instead.

This fixes the fault accounting in ptrace and the vsyscall debugging on
x86-64 (it needs the correct task_struct to map the vsyscall pages)

kernel/ptrace.c

@@ -168,7 +168,7 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
 		int bytes, ret, offset;
 		void *maddr;
 
-		ret = get_user_pages(current, mm, addr, 1,
+		ret = get_user_pages(tsk, mm, addr, 1,
 				write, 1, &page, &vma);
 		if (ret <= 0)
 			break;