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 1F658C001DE for ; Wed, 2 Aug 2023 06:54:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232565AbjHBGy3 (ORCPT ); Wed, 2 Aug 2023 02:54:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232589AbjHBGyE (ORCPT ); Wed, 2 Aug 2023 02:54:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 256E7E48 for ; Tue, 1 Aug 2023 23:53:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B843B6146C for ; Wed, 2 Aug 2023 06:53:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C501FC433C7; Wed, 2 Aug 2023 06:53:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690959232; bh=fRSx8GX7ueA3owE+Dc/NjcSH2h7YGs+/BDhqUXRetUU=; h=Subject:To:Cc:From:Date:From; b=hWXfyUc0E0VLWeFqBITarcCxvR5eO8TfPCGlmHEg3FOShQMmVO4hSgxLEeDiZd73G W3XiKHuYGZ9XSe1uvo3xQQP2JLShUH90szSNBabACFVcvl1ZefDQXGCVV6amysi3D1 0RJRq4YFTfrWMZ37fHr6tMDNLz+jWTcuA+7xCnaE= Subject: FAILED: patch "[PATCH] selftests/rseq: Play nice with binaries statically linked" failed to apply to 6.1-stable tree To: seanjc@google.com, aaronlewis@google.com, pbonzini@redhat.com Cc: From: Date: Wed, 02 Aug 2023 08:53:41 +0200 Message-ID: <2023080241-yearning-swifter-0f9a@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 3bcbc20942db5d738221cca31a928efc09827069 # git commit -s git send-email --to '' --in-reply-to '2023080241-yearning-swifter-0f9a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 3bcbc20942db ("selftests/rseq: Play nice with binaries statically linked against glibc 2.35+") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 3bcbc20942db5d738221cca31a928efc09827069 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 21 Jul 2023 15:33:52 -0700 Subject: [PATCH] selftests/rseq: Play nice with binaries statically linked against glibc 2.35+ To allow running rseq and KVM's rseq selftests as statically linked binaries, initialize the various "trampoline" pointers to point directly at the expect glibc symbols, and skip the dlysm() lookups if the rseq size is non-zero, i.e. the binary is statically linked *and* the libc registered its own rseq. Define weak versions of the symbols so as not to break linking against libc versions that don't support rseq in any capacity. The KVM selftests in particular are often statically linked so that they can be run on targets with very limited runtime environments, i.e. test machines. Fixes: 233e667e1ae3 ("selftests/rseq: Uplift rseq selftests for compatibility with glibc-2.35") Cc: Aaron Lewis Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20230721223352.2333911-1-seanjc@google.com> Signed-off-by: Paolo Bonzini diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c index 4e4aa006004c..a723da253244 100644 --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -34,9 +34,17 @@ #include "../kselftest.h" #include "rseq.h" -static const ptrdiff_t *libc_rseq_offset_p; -static const unsigned int *libc_rseq_size_p; -static const unsigned int *libc_rseq_flags_p; +/* + * Define weak versions to play nice with binaries that are statically linked + * against a libc that doesn't support registering its own rseq. + */ +__weak ptrdiff_t __rseq_offset; +__weak unsigned int __rseq_size; +__weak unsigned int __rseq_flags; + +static const ptrdiff_t *libc_rseq_offset_p = &__rseq_offset; +static const unsigned int *libc_rseq_size_p = &__rseq_size; +static const unsigned int *libc_rseq_flags_p = &__rseq_flags; /* Offset from the thread pointer to the rseq area. */ ptrdiff_t rseq_offset; @@ -155,9 +163,17 @@ unsigned int get_rseq_feature_size(void) static __attribute__((constructor)) void rseq_init(void) { - libc_rseq_offset_p = dlsym(RTLD_NEXT, "__rseq_offset"); - libc_rseq_size_p = dlsym(RTLD_NEXT, "__rseq_size"); - libc_rseq_flags_p = dlsym(RTLD_NEXT, "__rseq_flags"); + /* + * If the libc's registered rseq size isn't already valid, it may be + * because the binary is dynamically linked and not necessarily due to + * libc not having registered a restartable sequence. Try to find the + * symbols if that's the case. + */ + if (!*libc_rseq_size_p) { + libc_rseq_offset_p = dlsym(RTLD_NEXT, "__rseq_offset"); + libc_rseq_size_p = dlsym(RTLD_NEXT, "__rseq_size"); + libc_rseq_flags_p = dlsym(RTLD_NEXT, "__rseq_flags"); + } if (libc_rseq_size_p && libc_rseq_offset_p && libc_rseq_flags_p && *libc_rseq_size_p != 0) { /* rseq registration owned by glibc */