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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E00EAC433DF for ; Thu, 21 May 2020 20:08:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B29C6207D3 for ; Thu, 21 May 2020 20:08:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PWo2KMZw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728034AbgEUUIU (ORCPT ); Thu, 21 May 2020 16:08:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726814AbgEUUIU (ORCPT ); Thu, 21 May 2020 16:08:20 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2868DC061A0E; Thu, 21 May 2020 13:08:20 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id v63so3936128pfb.10; Thu, 21 May 2020 13:08:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=XlSWxuTl8RjEPaaS0nAI4JGOmMxJguYdjCUdlJurYag=; b=PWo2KMZwDNbRJSev/kbOT/GF1wUZY6kZfMRdhCGAOLlqZsvgOgSVCp1Cd4jm2OkHbO XNCHBZHyB2e2mDvQrClWw7C0SWyKoZPFOYu/vdtG3k7CyAfFRDsGv9KRSct6DWf7Jqm7 ZCDfDedXOetN+eFaGvNZD+/doq/F1dRikc8YwpiRDgOMi1v+IuLqe7/UYvlla3fjV9lK ZLZvYVIIDH8iXOgvyaQIrzTiQZFC/PNg0I7Evo1K+uh54D8VIPZw3og9VJFO0izapgsW Uatc1qIt0blStgwS988+Dp7Q4QRV4Xz+UEfnqp7s7f4TCaxvx4kkZJ7/Mv428Ylvii5W +23w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=XlSWxuTl8RjEPaaS0nAI4JGOmMxJguYdjCUdlJurYag=; b=Q7mXI7xBKqhgIqX1R5gQwE2xaKuhBK2fIhtRaduUlw6CKNBy+lLtVKblYYnZbYrfUe gYagnINXYvSHV2B0+zsDzKlCY49MqKpwZFNGl/ZGyqqAlRRAvg8pLkf8XRgI4gjqs/eh 0wGcEogyKFcn6lygotuA5WLMYw8rFeDJtGQLBaPjnWrYJxZh1IUY1KdLiNej8fcFW0ra Uh2S42fmbxfvaGYqkX6mcF3UM1MgvYU3IvexR0ieG4IwBMBlKfI/0f/AObvHsk7kzCg6 4BnYp+a6KneBUyjEwKDzNNJ7yCOLQAUTils6weu1Uhj/Xnt57DlHTQAS+x+7VSn0znnT kgzg== X-Gm-Message-State: AOAM531zbzsNsjX/BYm2SF4gLS2AsAQjVXeplgAhwRJ49xkjKWAxP2YT oNJJuon+gHcG3miseM8mFWI= X-Google-Smtp-Source: ABdhPJwKnCFrNUy+vKYuUveKy8VR2bdYCGhEHCEL1yGDzUfcROQ4ecKTwOjvDzkNo4eLcCCkgXxRxQ== X-Received: by 2002:a63:cf17:: with SMTP id j23mr8541974pgg.373.1590091699768; Thu, 21 May 2020 13:08:19 -0700 (PDT) Received: from [127.0.1.1] ([184.63.162.180]) by smtp.gmail.com with ESMTPSA id d18sm5123513pfq.136.2020.05.21.13.08.11 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 May 2020 13:08:18 -0700 (PDT) Subject: [bpf-next PATCH v2 3/4] bpf: selftests, verifier case for non null pointer map value branch From: John Fastabend To: yhs@fb.com, andrii.nakryiko@gmail.com, ast@kernel.org, daniel@iogearbox.net Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, john.fastabend@gmail.com Date: Thu, 21 May 2020 13:08:06 -0700 Message-ID: <159009168650.6313.7434084136067263554.stgit@john-Precision-5820-Tower> In-Reply-To: <159009128301.6313.11384218513010252427.stgit@john-Precision-5820-Tower> References: <159009128301.6313.11384218513010252427.stgit@john-Precision-5820-Tower> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org When we have pointer type that is known to be non-null we only follow the non-null branch. This adds tests to cover the map_value pointer returned from a map lookup. To force an error if both branches are followed we do an ALU op on R10. Acked-by: Andrii Nakryiko Signed-off-by: John Fastabend --- .../testing/selftests/bpf/verifier/value_or_null.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/value_or_null.c b/tools/testing/selftests/bpf/verifier/value_or_null.c index 860d4a7..3ecb70a 100644 --- a/tools/testing/selftests/bpf/verifier/value_or_null.c +++ b/tools/testing/selftests/bpf/verifier/value_or_null.c @@ -150,3 +150,22 @@ .result_unpriv = REJECT, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, +{ + "map lookup and null branch prediction", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, 10), + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2), + BPF_JMP_IMM(BPF_JNE, BPF_REG_6, 0, 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_10, 10), + BPF_EXIT_INSN(), + }, + .fixup_map_hash_8b = { 4 }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, +},