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-rw-r--r--arch/x86/kernel/process_64.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e2319f39988..c6eb5c91e5f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -294,6 +294,7 @@ void flush_thread(void)
/*
* Forget coprocessor state..
*/
+ tsk->fpu_counter = 0;
clear_fpu(tsk);
clear_used_math();
}
@@ -658,8 +659,11 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/* If the task has used fpu the last 5 timeslices, just do a full
* restore of the math state immediately to avoid the trap; the
* chances of needing FPU soon are obviously high now
+ *
+ * tsk_used_math() checks prevent calling math_state_restore(),
+ * which can sleep in the case of !tsk_used_math()
*/
- if (next_p->fpu_counter>5)
+ if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
math_state_restore();
return prev_p;
}