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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C940BC43217 for ; Mon, 27 Sep 2021 15:00:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1CD160FF2 for ; Mon, 27 Sep 2021 15:00:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234945AbhI0PCT (ORCPT ); Mon, 27 Sep 2021 11:02:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234996AbhI0PCC (ORCPT ); Mon, 27 Sep 2021 11:02:02 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03DBEC061740; Mon, 27 Sep 2021 08:00:18 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id s75so1540117pgs.5; Mon, 27 Sep 2021 08:00:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HAo200QE9/huK+nWNKe5juvI7U/KIFLH0A3znfnQYDM=; b=G4uzPoyz5U7he4rqhKyzV9PdfXoNM1wZUs9RQGDfCHDLwAzq/vYuMWIBC39lPiDEzY GfA2kFxAnm2afuHzfq19koDb0fCItoQ9fdYdixMtSBnkW1d0UW0xB+NzUpolJbMQx2DI oYi03lP7Trn0sMQBjao+lbE6Ro9rG+5HnsAyU6UUqoaF96FNddLEWS85DGzPrxsA0Hzz GiQa7ZXaOBDd0mSibtEvYgQok9OKVX4ZFjxRa1uSYvaqb8wY/pUrR3Eus3XzvN0cgY85 dJAEYlba6JhZ/TywAcziGWSZT7lA3BoVgMUqbt0xLJHQDBv4WO3xWYhFppNhv7lFtDky xLFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HAo200QE9/huK+nWNKe5juvI7U/KIFLH0A3znfnQYDM=; b=olBX06XC+eZxmTc3Ty6UqAwX2gYZFMpWDlKYcbgHi4hZQ3lAfGvJI6WCvwvkSycpGF AsP6At5t2oxzcapyM+pJ7wAOvosRUYrkYhDJRkARwnLqIkQWJlZI6PkdrPKjJzihLSkO LdyUxbdmnPb5DCLVpMxu/ET3pxk2Ds1YBFn4fknwdZQd+5wvwQ5eobnUUkksHu2rh9IJ PdfK1z3mpI4OwpTkcZnImpt1ZLo+CGaW4s2YDxkcSjkKHvY0N69iAMneOkteYVmf/9pY RYbs1cPmdz4N9TA3ki9MV90khLdpwbKQfY42mIwEUPAgr81FUOGuOr0MEe28WRlke1ms H89Q== X-Gm-Message-State: AOAM533zna6GetSJh8gRNvkXO5aCDyEZmUrYwOuUBfOl7kNguuRlsRO6 hlrppR7p8KYvhYSWlGu9nzOpc45GYRo= X-Google-Smtp-Source: ABdhPJyqk7wr4DiStlyvCNzbEhOxLauKxA0qxSBVRSKDs33S0cxej4mdoOkpEvKpy6Ril6TGG/cksA== X-Received: by 2002:a62:2587:0:b0:44b:2d81:8520 with SMTP id l129-20020a622587000000b0044b2d818520mr100916pfl.43.1632754817176; Mon, 27 Sep 2021 08:00:17 -0700 (PDT) Received: from localhost ([2405:201:6014:d058:a28d:3909:6ed5:29e7]) by smtp.gmail.com with ESMTPSA id x13sm17450357pfp.133.2021.09.27.08.00.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Sep 2021 08:00:16 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Kumar Kartikeya Dwivedi , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , Jesper Dangaard Brouer , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , netdev@vger.kernel.org Subject: [PATCH bpf-next v5 10/12] libbpf: Fix skel_internal.h to set errno on loader retval < 0 Date: Mon, 27 Sep 2021 20:29:39 +0530 Message-Id: <20210927145941.1383001-11-memxor@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927145941.1383001-1-memxor@gmail.com> References: <20210927145941.1383001-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1647; h=from:subject; bh=PVTKS+rfPpxdSU9d74iSymeJVwfhEWVxpXAvuJFJ9qs=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBhUdxPrACVEi7CiY1lhZ+7KHtZuFVP74ebqAo6CHjW 2E6erlWJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCYVHcTwAKCRBM4MiGSL8RyvLkD/ 44fEfgf6NG+0oe9IJLBj4cCxNZ5Zsfu2h0U4i2h24cw6PYDoSzrGjwvnMRsEDfUQliloPhwU5zT/zI J+U6jFNkxQ1WfCKksOHKbDaiGdWHxFAr9OzqQuIs6JD5Dvla9FntOa/aCPP2eAl54gd2E0NOt9li+J g2phHQhrofK690XQJRmb5302zDf/fHa6LX+nefl8bxVRWQuYx4zSOsEy7lHYqtXyHwTEPYrEBf43Wt +IoRpkWeEM88z2ciLkeQhMhghXtI4kvCX4+uMwgpNDQ5mthpV1Ch+PaPZAmYcMqlD5x2c3938ZIRdA YC5Sf2iTpN++d9CC239Io112EAW0cahlQw9GlI9uFJR9bITdb5BrYeisJveOOphy8JAbEd7zCHDkDa iiu8Ue3uKDvJry6VY2baeOzYYOnNfH3PtjIwqgywDoPfVATRyp3FskJFLgYvNcx9LW5b+yGHyqOf9P Dy/te3xFSEeMEb28PcM7DJBuJ7TuUz+V8c9qDSziXB2WbwO3cbpiXmiOjPxZpLp/vmGAgsw5ebUzAP /7sMP49qhEmUwI175tqWGG86CrmA7Lg15Yl3pf9FUQYNf63AtaR/JdoX74UOpQOeqmejyKL6s547+o yTNpLlfMic+rl43Fuuvp0Drk0rPhKm6xi6oRUs31gLlfX4VlEc+IpazALcqg== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org When the loader indicates an internal error (result of a checked bpf system call), it returns the result in attr.test.retval. However, tests that rely on ASSERT_OK_PTR on NULL (returned from light skeleton) may miss that NULL denotes an error if errno is set to 0. This would result in skel pointer being NULL, while ASSERT_OK_PTR returning 1, leading to a SEGV on dereference of skel, because libbpf_get_error relies on the assumption that errno is always set in case of error for ptr == NULL. In particular, this was observed for the ksyms_module test. When executed using `./test_progs -t ksyms`, prior tests manipulated errno and the test didn't crash when it failed at ksyms_module load, while using `./test_progs -t ksyms_module` crashed due to errno being untouched. Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.) Signed-off-by: Kumar Kartikeya Dwivedi --- tools/lib/bpf/skel_internal.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h index b22b50c1b173..9cf66702fa8d 100644 --- a/tools/lib/bpf/skel_internal.h +++ b/tools/lib/bpf/skel_internal.h @@ -105,10 +105,12 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts) err = skel_sys_bpf(BPF_PROG_RUN, &attr, sizeof(attr)); if (err < 0 || (int)attr.test.retval < 0) { opts->errstr = "failed to execute loader prog"; - if (err < 0) + if (err < 0) { err = -errno; - else + } else { err = (int)attr.test.retval; + errno = -err; + } goto out; } err = 0; -- 2.33.0