From d5d54da0eae152dea77df18bef5a24eca1ae35c4 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 17 Aug 2020 09:55:40 +0200
Subject: [PATCH] Kernel: Don't use copy_from_user() for kernelspace read in
 perf events

Fixes #3182.
---
 Kernel/PerformanceEventBuffer.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Kernel/PerformanceEventBuffer.cpp b/Kernel/PerformanceEventBuffer.cpp
index cb6fe2fb04..6e4f4b2db8 100644
--- a/Kernel/PerformanceEventBuffer.cpp
+++ b/Kernel/PerformanceEventBuffer.cpp
@@ -66,9 +66,8 @@ KResult PerformanceEventBuffer::append(int type, FlatPtr arg1, FlatPtr arg2)
     FlatPtr ebp;
     asm volatile("movl %%ebp, %%eax"
                  : "=a"(ebp));
-    FlatPtr eip;
     auto current_thread = Thread::current();
-    copy_from_user(&eip, (FlatPtr*)&current_thread->get_register_dump_from_stack().eip);
+    auto eip = current_thread->get_register_dump_from_stack().eip;
     Vector<FlatPtr> backtrace;
     {
         SmapDisabler disabler;