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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 8B595C433FF for ; Sun, 28 Jul 2019 15:28:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A1512077C for ; Sun, 28 Jul 2019 15:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726305AbfG1P26 (ORCPT ); Sun, 28 Jul 2019 11:28:58 -0400 Received: from foss.arm.com ([217.140.110.172]:33526 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726046AbfG1P25 (ORCPT ); Sun, 28 Jul 2019 11:28:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0B7A4344; Sun, 28 Jul 2019 08:28:57 -0700 (PDT) Received: from [10.37.12.40] (unknown [10.37.12.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AEBAD3F71F; Sun, 28 Jul 2019 08:28:55 -0700 (PDT) Subject: Re: [patch 1/5] lib/vdso/32: Remove inconsistent NULL pointer checks To: Thomas Gleixner , LKML Cc: x86@kernel.org, Andy Lutomirski , Sean Christopherson , Kees Cook , Paul Bolle , Will Deacon References: <20190728131251.622415456@linutronix.de> <20190728131648.587523358@linutronix.de> From: Vincenzo Frascino Message-ID: Date: Sun, 28 Jul 2019 16:30:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190728131648.587523358@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/28/19 2:12 PM, Thomas Gleixner wrote: > The 32bit variants of vdso_clock_gettime()/getres() have a NULL pointer > check for the timespec pointer. That's inconsistent vs. 64bit. > > But the vdso implementation will never be consistent versus the syscall > because the only case which it can handle is NULL. Any other invalid > pointer will cause a segfault. So special casing NULL is not really useful. > > Remove it along with the superflouos syscall fallback invocation as that > will return -EFAULT anyway. That also gets rid of the dubious typecast > which only works because the pointer is NULL. Reviewed-by: Vincenzo Frascino Tested-by: Vincenzo Frascino > > Fixes: 00b26474c2f1 ("lib/vdso: Provide generic VDSO implementation") > Signed-off-by: Thomas Gleixner > --- > lib/vdso/gettimeofday.c | 18 ++---------------- > 1 file changed, 2 insertions(+), 16 deletions(-) > > --- a/lib/vdso/gettimeofday.c > +++ b/lib/vdso/gettimeofday.c > @@ -115,9 +115,6 @@ static __maybe_unused int > struct __kernel_timespec ts; > int ret; > > - if (res == NULL) > - goto fallback; > - > ret = __cvdso_clock_gettime(clock, &ts); > > if (ret == 0) { > @@ -126,9 +123,6 @@ static __maybe_unused int > } > > return ret; > - > -fallback: > - return clock_gettime_fallback(clock, (struct __kernel_timespec *)res); > } > > static __maybe_unused int > @@ -204,10 +198,8 @@ int __cvdso_clock_getres(clockid_t clock > goto fallback; > } > > - if (res) { > - res->tv_sec = 0; > - res->tv_nsec = ns; > - } > + res->tv_sec = 0; > + res->tv_nsec = ns; > > return 0; > > @@ -221,9 +213,6 @@ static __maybe_unused int > struct __kernel_timespec ts; > int ret; > > - if (res == NULL) > - goto fallback; > - > ret = __cvdso_clock_getres(clock, &ts); > > if (ret == 0) { > @@ -232,8 +221,5 @@ static __maybe_unused int > } > > return ret; > - > -fallback: > - return clock_getres_fallback(clock, (struct __kernel_timespec *)res); > } > #endif /* VDSO_HAS_CLOCK_GETRES */ > > -- Regards, Vincenzo