3 files changed, 18 insertions, 4 deletions

diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index b45ef8ddd651..ca316b5b742c 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -104,7 +104,16 @@ static inline int restore_i387(struct _fpstate __user *buf)
                 clts();
                 task_thread_info(current)->status |= TS_USEDFPU;
         }
-        return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
+        err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
+        if (unlikely(err)) {
+                /*
+                 * Encountered an error while doing the restore from the
+                 * user buffer, clear the fpu state.
+                 */
+                clear_fpu(tsk);
+                clear_used_math();
+        }
+        return err;
 }
 
 /*
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 3f18d73f420c..513caaca7115 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -1131,7 +1131,14 @@ asmlinkage void math_state_restore(void)
         }
 
         clts();                         /* Allow maths ops (or we recurse) */
-        restore_fpu_checking(&me->thread.xstate->fxsave);
+        /*
+         * Paranoid restore. send a SIGSEGV if we fail to restore the state.
+         */
+        if (unlikely(restore_fpu_checking(&me->thread.xstate->fxsave))) {
+                stts();
+                force_sig(SIGSEGV, me);
+                return;
+        }
         task_thread_info(me)->status |= TS_USEDFPU;
         me->fpu_counter++;
 }
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index 6f60a6b89973..3958de6aad0e 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -62,8 +62,6 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
 #else
                      : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
 #endif
-        if (unlikely(err))
-                init_fpu(current);
         return err;
 }