Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932845AbaKRPKA (ORCPT ); Tue, 18 Nov 2014 10:10:00 -0500 Received: from cantor2.suse.de ([195.135.220.15]:56973 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754954AbaKROJh (ORCPT ); Tue, 18 Nov 2014 09:09:37 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Oleg Nesterov , "H. Peter Anvin" , Jiri Slaby Subject: [PATCH 3.12 067/206] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() Date: Tue, 18 Nov 2014 15:07:02 +0100 Message-Id: <03f43efc6a00eb29015222f8e9caeafdd9986a63.1416319692.git.jslaby@suse.cz> X-Mailer: git-send-email 2.1.3 In-Reply-To: <28f04bcc068a44c5641c727883947960fb8dcbd5.1416319692.git.jslaby@suse.cz> References: <28f04bcc068a44c5641c727883947960fb8dcbd5.1416319692.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleg Nesterov 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 422fd8223470..7305625c2767 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 { -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/