---

yaml
---
r: 6980
b: refs/heads/master
c: e7a2ff5
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2f2984eb4afb2a4298e3186cb49cc7e88dd6d929
+refs/heads/master: e7a2ff593c0e48b130434dee4d2fd3452a850e6f

trunk/arch/i386/kernel/process.c

@@ -678,21 +678,26 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas
 	__unlazy_fpu(prev_p);
 
 	/*
-	 * Reload esp0, LDT and the page table pointer:
+	 * Reload esp0.
 	 */
 	load_esp0(tss, next);
 
 	/*
-	 * Load the per-thread Thread-Local Storage descriptor.
+	 * Save away %fs and %gs. No need to save %es and %ds, as
+	 * those are always kernel segments while inside the kernel.
+	 * Doing this before setting the new TLS descriptors avoids
+	 * the situation where we temporarily have non-reloadable
+	 * segments in %fs and %gs.  This could be an issue if the
+	 * NMI handler ever used %fs or %gs (it does not today), or
+	 * if the kernel is running inside of a hypervisor layer.
 	 */
-	load_TLS(next, cpu);
+	savesegment(fs, prev->fs);
+	savesegment(gs, prev->gs);
 
 	/*
-	 * Save away %fs and %gs. No need to save %es and %ds, as
-	 * those are always kernel segments while inside the kernel.
+	 * Load the per-thread Thread-Local Storage descriptor.
 	 */
-	asm volatile("mov %%fs,%0":"=m" (prev->fs));
-	asm volatile("mov %%gs,%0":"=m" (prev->gs));
+	load_TLS(next, cpu);
 
 	/*
 	 * Restore %fs and %gs if needed.