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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77D0EC19F28 for ; Wed, 3 Aug 2022 16:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238127AbiHCQLC (ORCPT ); Wed, 3 Aug 2022 12:11:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236287AbiHCQLA (ORCPT ); Wed, 3 Aug 2022 12:11:00 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 383B232EDC for ; Wed, 3 Aug 2022 09:10:59 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id s5-20020a17090a13c500b001f4da9ffe5fso2496734pjf.5 for ; Wed, 03 Aug 2022 09:10:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc; bh=P8Kl/xKU4IYrDHB8lVGv34ItbSelul5121WYDgLOaI0=; b=AxI/+//w2k08IiKw07QSnQ9ESu4dwG+wQ2H1SGE72Li0sSxNMpJ1h74H0Sl4CJKqsa ih4rUvBv/IKrC+E+wGXXNKFxSl7R7LsDyo7QhY8j3ZKQFk/x5XOWF3SohPzArzZc4FId y0S0s1uCBL7zRxZmyrax7xPhctcK9wyQJl1iQa3qwhzZBZ1qUWh6cU1SwH23tg25LmC8 jBcT2MqicnNp3pX3l51BnQDlLyL6gz89Z9nzF04zcjcJZEzZWF8b1I0ueoZnVcTP6M/F 8B2+3QzRsv2P/2XqGNrJUbuo11iswfZMfh/VT12eZ01MuohkIatWG1v+qHWPimCnW99S FJPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=P8Kl/xKU4IYrDHB8lVGv34ItbSelul5121WYDgLOaI0=; b=x9vfZJ2MYwiCHM9c0MuSVZMKXPdKt9aqUOHRQ3SyB/cCN3p7jfNsh1E3pY8HA9kKBq i2W8AMfqAA8CB2jBcP46UJ1kl6elf0vN3RIoI0+s/JDNGHdNNp7RJwXOlK8zTOarYbbr esqXAUXw+ZXYe1R/wYSB5/g0xW/LTxybI4uvRXgsbOv1oWRW77KY8INhqe/gnxBDZiKf 3CKaXzhSKkekLR/gP/bPyQjOrGW6mQO4gKJbFED3RHE4vvPO0DT6eWEylB3AYncHAird gQWUyE795z3JlDI5sTGusURwkGlw+DDX5KNLD8aOqQHc4cQiFKqAOoFn7guut90TzuU+ Eybw== X-Gm-Message-State: ACgBeo27UYcxG3IvAtyjm8x5FPXI2ezxzRPfzBgSqwY/s/FIK9UBxB9p a5kTjjlcb7UMjWK7IeefF4qJ5Q== X-Google-Smtp-Source: AA6agR5JGK8PeZUbKGzAWb+OwiWFpZoHLTuXqycARkDvNa2Nl3oOUNhgSpR3SKoJI1jAkIYufUZsSw== X-Received: by 2002:a17:90a:b010:b0:1f3:161c:30a0 with SMTP id x16-20020a17090ab01000b001f3161c30a0mr5426664pjq.243.1659543058557; Wed, 03 Aug 2022 09:10:58 -0700 (PDT) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id d9-20020a170903230900b0016f057b88c9sm2226388plh.26.2022.08.03.09.10.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Aug 2022 09:10:57 -0700 (PDT) Date: Wed, 3 Aug 2022 16:10:53 +0000 From: Sean Christopherson To: Andrew Jones Cc: Jinrong Liang , Paolo Bonzini , Wanpeng Li , Jim Mattson , Vitaly Kuznetsov , Joerg Roedel , Jinrong Liang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests: kvm: Fix a compile error in selftests/kvm/rseq_test.c Message-ID: References: <20220802071240.84626-1-cloudliang@tencent.com> <20220802150830.rgzeg47enbpsucbr@kamzik> <20220803142637.3y5fj2cwyvbrwect@kamzik> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220803142637.3y5fj2cwyvbrwect@kamzik> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 03, 2022, Andrew Jones wrote: > On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote: > > My ldd version is (GNU libc) 2.28, and I get a compilation error in this case. > > But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine. > > This shows that compilation errors may occur in different GNU libc environments. > > Would it be more appropriate to use syscall for better compatibility? > > OK, it's a pity, but no big deal to use syscall(). Ya, https://man7.org/linux/man-pages/man2/gettid.2.html says: The gettid() system call first appeared on Linux in kernel 2.4.11. Library support was added in glibc 2.30. But there are already two other instances of syscall(SYS_gettid) in KVM selftests, tools/testing/selftests/kvm/lib/assert.c even adds a _gettid() wrapper. So rather than having to remember (or discover) to use syscall(SYS_gettid), I wonder if it's possible to conditionally define gettid()? E.g. check for GLIBC version? Or do #define gettid() syscall(SYS_gettid) so that it's always available and simply overrides the library's gettid() if it's provided?