From eb3975c8907cc9cab47c3759faf653101c8aec95 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 2 Sep 2014 19:57:17 +0200 Subject: [PATCH 1/1] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() commit df24fb859a4e200d9324e2974229fbb7adf00aef upstream. Add preempt_disable() + preempt_enable() around math_state_restore() in __restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin() can overwrite fpu->state we are going to restore. Signed-off-by: Oleg Nesterov Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com Reviewed-by: Suresh Siddha Signed-off-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/xsave.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index a4b451c..4679ef4 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -399,8 +399,11 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) set_used_math(); } - if (use_eager_fpu()) + if (use_eager_fpu()) { + preempt_disable(); math_state_restore(); + preempt_enable(); + } return err; } else { -- 2.7.4