From 36226163fa48ee2c5f73bd2e870ce2e5a057f42e Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Fri, 9 Jul 2021 20:38:18 -0400
Subject: [PATCH] x86: Mark the trapframe as initialized in
 ipi_bitmap_handler()

Otherwise KASAN may generate false positives if the trapframe was
written into a poisoned region of the stack.

Reported by:	pho
Reported by:	syzbot+ee60455cd58e6eed20c9@syzkaller.appspotmail.com
Reported by:	syzbot+be5f9df26426ace3a00c@syzkaller.appspotmail.com
Sponsored by:	The FreeBSD Foundation
---
 sys/x86/x86/mp_x86.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c
index 2dcdf923c46..1f22b3a7886 100644
--- a/sys/x86/x86/mp_x86.c
+++ b/sys/x86/x86/mp_x86.c
@@ -41,6 +41,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/asan.h>
 #include <sys/bus.h>
 #include <sys/cons.h>	/* cngetc() */
 #include <sys/cpuset.h>
@@ -1279,6 +1280,8 @@ ipi_bitmap_handler(struct trapframe frame)
 	int cpu = PCPU_GET(cpuid);
 	u_int ipi_bitmap;
 
+	kasan_mark(&frame, sizeof(frame), sizeof(frame), 0);
+
 	td = curthread;
 	ipi_bitmap = atomic_readandclear_int(&cpuid_to_pcpu[cpu]->
 	    pc_ipi_bitmap);