From df24fb859a4e200d9324e2974229fbb7adf00aef Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 2 Sep 2014 19:57:17 +0200 Subject: [PATCH] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() 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 Cc: # v3.7+ Reviewed-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- 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 cf0b83040ec8..4c540c4719d8 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -400,8 +400,11 @@ 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 { -- 2.39.2