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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 D163BC10F03 for ; Mon, 25 Mar 2019 16:23:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E16E20828 for ; Mon, 25 Mar 2019 16:23:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="a4p6XGps" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729322AbfCYQXg (ORCPT ); Mon, 25 Mar 2019 12:23:36 -0400 Received: from mail-it1-f195.google.com ([209.85.166.195]:55922 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbfCYQXg (ORCPT ); Mon, 25 Mar 2019 12:23:36 -0400 Received: by mail-it1-f195.google.com with SMTP id z126so14850471itd.5 for ; Mon, 25 Mar 2019 09:23:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=5RYC5QkNPmWnV7M+cp152sH2vhCRnoMiK4CZtvvJh04=; b=a4p6XGpsh4XKbVLZAa544N9Eyip02ETThXf36Kzdq2N67nSugtAGMj8ZW02ZXjqcBo dGqv7gA4t4WGd4x9Zbe1UF99alCbkWJM56ao7ntWpb5lvOLioWPPDXd4q8TAN10gAsi7 AakLjcW6gu94dkOkHpnZ4QUGGZPcF7ihTOTOtMQo1nP7Mw6r9DScn8NuMglhLQZtsV/v Ck5jE1PkfUR8r0LOZyyd3I6PzzP+TuAEpr6tCQ3BzlK6CvBCTWJVQcImhu6Rz0S64t9O XxRvJs+xo95Fz0UI0U6bgSmCt0ckkICGnrEtwE16vSxtoMypxGAKYQyA6nH5l5+sw2x8 E/JA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=5RYC5QkNPmWnV7M+cp152sH2vhCRnoMiK4CZtvvJh04=; b=pltlV75CbN8Xa1cPV6kyws+mEg8EbxLl8MjNyu2LOyG7w1dPVnIIpCkx+AjI4AYYXh /xdf6VvqZioy3bEb9l7LdzlWw8Ql1w3AM5IqjlpFTZlMoVTkBj8YWriBcvCIj/yKeVjb i1WPgxGltfrZkHiqySZh4qlAOU1Lp9TE4q3BHNIDlmQAjDOJTctz2R8uHnZ/JU3lhXM8 o4yRSVRF1czPhLltx3ZL6+oSVFvA1C+ZTENlgdXuJHuAMall4UjkzZmnJrEY566tp0OM 1DpOIEmSHj1HHVFgk1kn/93Jdmj0LsqCVUGiZ+p9bKLevRp/535/G2+bjYXtuKiPqsQ8 ww5A== X-Gm-Message-State: APjAAAX7YAQVkJKatIFfz16MjOUIcEKSWiOIQ26N7FBcll+NtUAnBcoN mAApYYgdf0a/lIjzLTUWP2tTgQ== X-Google-Smtp-Source: APXvYqzTFUytd6hF1JTNnC7hNWzLdzWp0tAu433Pimy4C35zggJYDouZ4iACNnRfPcoKlOa0F90WEg== X-Received: by 2002:a24:6794:: with SMTP id u142mr9064550itc.84.1553531015661; Mon, 25 Mar 2019 09:23:35 -0700 (PDT) Received: from [192.168.1.158] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id o11sm5992146itb.33.2019.03.25.09.23.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Mar 2019 09:23:34 -0700 (PDT) Subject: Re: [PATCH 1/2] io_uring: fix big-endian compat signal mask handling To: James Bottomley , Arnd Bergmann , Andrew Morton Cc: Alexander Viro , Hannes Reinecke , Matthew Wilcox , David Hildenbrand , Nikolay Borisov , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190325143521.34928-1-arnd@arndb.de> <1553530766.2955.51.camel@HansenPartnership.com> From: Jens Axboe Message-ID: <4c77d293-8eb9-01aa-27f8-7f320082e182@kernel.dk> Date: Mon, 25 Mar 2019 10:23:33 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <1553530766.2955.51.camel@HansenPartnership.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 3/25/19 10:19 AM, James Bottomley wrote: > On Mon, 2019-03-25 at 15:34 +0100, Arnd Bergmann wrote: >> On big-endian architectures, the signal masks are differnet >> between 32-bit and 64-bit tasks, so we have to use a different >> function for reading them from user space. >> >> io_cqring_wait() initially got this wrong, and always interprets >> this as a native structure. This is ok on x86 and most arm64, >> but not on s390, ppc64be, mips64be, sparc64 and parisc. >> >> Signed-off-by: Arnd Bergmann >> --- >> fs/io_uring.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/fs/io_uring.c b/fs/io_uring.c >> index 6aaa30580a2b..8f48d29abf76 100644 >> --- a/fs/io_uring.c >> +++ b/fs/io_uring.c >> @@ -1968,7 +1968,15 @@ static int io_cqring_wait(struct io_ring_ctx >> *ctx, int min_events, >> return 0; >> >> if (sig) { >> - ret = set_user_sigmask(sig, &ksigmask, &sigsaved, >> sigsz); >> +#ifdef CONFIG_COMPAT >> + if (in_compat_syscall()) >> + ret = set_compat_user_sigmask((const >> compat_sigset_t __user *)sig, >> + &ksigmask, >> &sigsaved, sigsz); >> + else >> +#endif > > This looks a bit suboptimal: shouldn't in_compat_syscall() be hard > coded to return 0 if CONFIG_COMPAT isn't defined? That way the > compiler can do the correct optimization and we don't have to litter > #ifdefs and worry about undefined variables and other things. That requires the types to be valid for !CONFIG_COMPAT, as well as the sigmask helper. -- Jens Axboe