x86: fix fpu restore from sig return
If the task never used fpu, initialize the fpu before restoring the FP
state from the signal handler context. This will allocate the fpu
state, if the task never needed it before.
Reported-and-bisected-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Frederik Deweerdt <deweerdt@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index da2adb4..6b722d3 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -175,7 +175,15 @@
*/
static inline int restore_i387(struct _fpstate __user *buf)
{
- set_used_math();
+ struct task_struct *tsk = current;
+ int err;
+
+ if (!used_math()) {
+ err = init_fpu(tsk);
+ if (err)
+ return err;
+ }
+
if (!(task_thread_info(current)->status & TS_USEDFPU)) {
clts();
task_thread_info(current)->status |= TS_USEDFPU;