From: Rik van Riel <[email protected]> It is possible to hit fpu_copy in eager fpu mode, but without the current task's FPU context actually loaded into the CPU.
In that case, we should copy the FPU context from memory, not save it from registers. Signed-off-by: Rik van Riel <[email protected]> --- arch/x86/include/asm/fpu-internal.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 8546c0a..095dacc 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -594,7 +594,8 @@ static inline void fpu_free(struct fpu *fpu) static inline void fpu_copy(struct task_struct *dst, struct task_struct *src) { - if (use_eager_fpu()) { + preempt_disable(); + if (use_eager_fpu() && __thread_has_fpu(src)) { memset(&dst->thread.fpu.state->xsave, 0, xstate_size); __save_fpu(dst); } else { @@ -604,6 +605,7 @@ static inline void fpu_copy(struct task_struct *dst, struct task_struct *src) unlazy_fpu(src); memcpy(dfpu->state, sfpu->state, xstate_size); } + preempt_enable(); } static inline unsigned long -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
