Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph...

[~andy/linux] / arch / x86 / kernel / i387.c

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index e8368c6dd2a2988c2d9d68cacc7030554424ad70..d5dd808144190ffd1d443229b4dbbd56740fface 100644 (file)
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -86,10 +86,19 @@ EXPORT_SYMBOL(__kernel_fpu_begin);
 
 void __kernel_fpu_end(void)
 {
-       if (use_eager_fpu())
-               math_state_restore();
-       else
+       if (use_eager_fpu()) {
+               /*
+                * For eager fpu, most the time, tsk_used_math() is true.
+                * Restore the user math as we are done with the kernel usage.
+                * At few instances during thread exit, signal handling etc,
+                * tsk_used_math() is false. Those few places will take proper
+                * actions, so we don't need to restore the math here.
+                */
+               if (likely(tsk_used_math(current)))
+                       math_state_restore();
+       } else {
                stts();
+       }
 }
 EXPORT_SYMBOL(__kernel_fpu_end);