From 3d60169ef4461d949f33fbf1f3825b23484203e2 Mon Sep 17 00:00:00 2001
From: Peter Wemm <peter@FreeBSD.org>
Date: Sun, 23 Mar 2008 22:44:56 +0000
Subject: [PATCH] Protect the setting of the fsbase/gsbase MSR registers and
 the pcb_[fg]sbase values with a critical section, like the rest of the
 kernel.

---
 sys/amd64/ia32/ia32_signal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c
index a6d82a447cd..5849d0d8604 100644
--- a/sys/amd64/ia32/ia32_signal.c
+++ b/sys/amd64/ia32/ia32_signal.c
@@ -715,10 +715,12 @@ ia32_setregs(td, entry, stack, ps_strings)
 	struct trapframe *regs = td->td_frame;
 	struct pcb *pcb = td->td_pcb;
 	
+	critical_enter();
 	wrmsr(MSR_FSBASE, 0);
 	wrmsr(MSR_KGSBASE, 0);	/* User value while we're in the kernel */
 	pcb->pcb_fsbase = 0;
 	pcb->pcb_gsbase = 0;
+	critical_exit();
 	load_ds(_udatasel);
 	load_es(_udatasel);
 	load_fs(_udatasel);