From patchwork Tue Nov 25 10:37:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 414571 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 6CE57140100; Tue, 25 Nov 2014 21:56:35 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1XtDnM-00021T-6R; Tue, 25 Nov 2014 10:56:32 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1XtDYn-0002bE-Nv for kernel-team@lists.ubuntu.com; Tue, 25 Nov 2014 10:41:29 +0000 Received: from bl15-150-46.dsl.telepac.pt ([188.80.150.46] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1XtDYn-0001sS-HN; Tue, 25 Nov 2014 10:41:29 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.16.y-ckt 090/254] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() Date: Tue, 25 Nov 2014 10:37:20 +0000 Message-Id: <1416912004-5928-91-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1416912004-5928-1-git-send-email-luis.henriques@canonical.com> References: <1416912004-5928-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: "H. Peter Anvin" , Oleg Nesterov X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.16.7-ckt2 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov 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: Luis Henriques --- 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 a4b451c6addf..4679ef4005da 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 {