[PATCH] x86_64: Fix dump_trace()

If caller passed the tsk, we should use it to validate a stack ptr.
Otherwise, sysrq-t and other debugging stuff doesn't work.
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/traps.c

@@ -319,7 +319,7 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
 	/*
 	 * This handles the process stack:
 	 */
-	tinfo = current_thread_info();
+	tinfo = task_thread_info(tsk);
 	HANDLE_STACK (valid_stack_ptr(tinfo, stack));
 #undef HANDLE_STACK
 	put_cpu();