From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 738DFC433F5 for ; Wed, 8 Sep 2021 13:30:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61E0C61207 for ; Wed, 8 Sep 2021 13:30:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351848AbhIHNb1 (ORCPT ); Wed, 8 Sep 2021 09:31:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351676AbhIHNak (ORCPT ); Wed, 8 Sep 2021 09:30:40 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF47EC0613CF for ; Wed, 8 Sep 2021 06:29:32 -0700 (PDT) Message-ID: <20210908132525.679356300@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1631107771; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=5jeOxW36H43fKDkv84NoCQksuL/87wmqW6kiz8q5LY0=; b=aWCbvSnVW2+kbRs4n2ojuT5h2QDdbPEphwBghhmnX3Wh+xxYksOHpDk7UaqD7msbFvdFHn ZlpAS/n3J6ytPj206pyaw8e/ag9VOsju2svD43vv6N0qhkoiNLbcVMcskv5ow2NwVDzi9k wwmBLXEwlzzieqlrfI/iYfZyLr53lj5rL2it4zgeD0Ldv0VRgsJFUT9LehhrfKFPXwCtNY Ypp5Msr65Q/3pjrM0pZCghQDcvagW7lYQRQaitZNiPHqtSgXkJXjGGinJiMdVQDnGet0Zx YRTiRY9bdCNcSriZiG6f3XVL+OEE2NLHG6PqvE/a95+HcrX3F+VCkSrFpG4yRA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1631107771; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=5jeOxW36H43fKDkv84NoCQksuL/87wmqW6kiz8q5LY0=; b=vQFGfsSP0BtyFH8yue4R8TtwlYYvFxAvI6yunadKMWI/cAMgoBVRBfbMLpdYvQKxoZ2yMU WHlPorDoNYaQxGAA== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Al Viro , Linus Torvalds , Tony Luck , Alexei Starovoitov , Peter Ziljstra , Song Liu , Daniel Borkmann Subject: [patch V3 13/20] x86/fpu/signal: Move xstate clearing out of copy_fpregs_to_sigframe() References: <20210908130922.118265849@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Wed, 8 Sep 2021 15:29:30 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the direct saving of the FPU registers to the user space sigframe fails, copy_fpregs_to_sigframe() attempts to clear the user buffer. The most likely reason for such a fail is a page fault. As copy_fpregs_to_sigframe() is invoked with pagefaults disabled the chance that __clear_user() succeeds is minuscule. Move the clearing out into the caller which replaces the fault_in_pages_writeable() in that error handling path. The return value confusion will be cleaned up separately. Suggested-by: Al Viro Signed-off-by: Thomas Gleixner --- V3: Remove the bogus X86_TRAP_PF check --- arch/x86/kernel/fpu/signal.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -136,18 +136,12 @@ static inline int save_xstate_epilog(voi static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) { - int err; - if (use_xsave()) - err = xsave_to_user_sigframe(buf); - else if (use_fxsr()) - err = fxsave_to_user_sigframe((struct fxregs_state __user *) buf); + return xsave_to_user_sigframe(buf); + if (use_fxsr()) + return fxsave_to_user_sigframe((struct fxregs_state __user *) buf); else - err = fnsave_to_user_sigframe((struct fregs_state __user *) buf); - - if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size)) - err = -EFAULT; - return err; + return fnsave_to_user_sigframe((struct fregs_state __user *) buf); } /* @@ -218,9 +212,9 @@ int copy_fpstate_to_sigframe(void __user fpregs_unlock(); if (ret) { - if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size)) + if (!__clear_user(buf_fx, fpu_user_xstate_size)) goto retry; - return -EFAULT; + return -1; } /* Save the fsave header for the 32-bit frames. */