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=-24.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 6F54AC432BE for ; Sat, 14 Aug 2021 01:01:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ED9261042 for ; Sat, 14 Aug 2021 01:01:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236087AbhHNBB3 (ORCPT ); Fri, 13 Aug 2021 21:01:29 -0400 Received: from smtp-fw-33001.amazon.com ([207.171.190.10]:60653 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235870AbhHNBB2 (ORCPT ); Fri, 13 Aug 2021 21:01:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.co.jp; i=@amazon.co.jp; q=dns/txt; s=amazon201209; t=1628902862; x=1660438862; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=qedY7j3n4lJj1ou1ePjI/4MPlgHnzigr2lbey4ecztY=; b=V3cte5+KubA0n7dBK6whHX2CpgSGCIJCjdLUtG9k1e3NwsQALSb+3ucv nnwuDEXQMxYvAcKhjBq8LmGwxx213cPkiM0o0r6Ks4lqBvIMT6CKpFlyK YxNxQiH5sTLXcurYLHEou0MJAb33JoJ5dd9YdcU8Pthak2nxTA5HpSIKT E=; X-IronPort-AV: E=Sophos;i="5.84,320,1620691200"; d="scan'208";a="141723220" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-2a-119b4f96.us-west-2.amazon.com) ([10.43.8.2]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP; 14 Aug 2021 01:00:59 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-2a-119b4f96.us-west-2.amazon.com (Postfix) with ESMTPS id 8674F1A0939; Sat, 14 Aug 2021 01:00:57 +0000 (UTC) Received: from EX13D04ANC001.ant.amazon.com (10.43.157.89) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Sat, 14 Aug 2021 01:00:56 +0000 Received: from 88665a182662.ant.amazon.com (10.43.161.187) by EX13D04ANC001.ant.amazon.com (10.43.157.89) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Sat, 14 Aug 2021 01:00:45 +0000 From: Kuniyuki Iwashima To: CC: , , , , , , , , , , , , , , Subject: Re: [PATCH v5 bpf-next 3/4] selftest/bpf: Implement sample UNIX domain socket iterator program. Date: Sat, 14 Aug 2021 10:00:41 +0900 Message-ID: <20210814010041.38316-1-kuniyu@amazon.co.jp> X-Mailer: git-send-email 2.30.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.43.161.187] X-ClientProxiedBy: EX13D40UWC004.ant.amazon.com (10.43.162.175) To EX13D04ANC001.ant.amazon.com (10.43.157.89) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Andrii Nakryiko Date: Fri, 13 Aug 2021 17:26:05 -0700 > On Fri, Aug 13, 2021 at 5:21 PM Kuniyuki Iwashima wrote: > > > > From: Andrii Nakryiko > > Date: Fri, 13 Aug 2021 16:25:53 -0700 > > > On Thu, Aug 12, 2021 at 9:46 AM Kuniyuki Iwashima wrote: > > > > > > > > The iterator can output almost the same result compared to /proc/net/unix. > > > > The header line is aligned, and the Inode column uses "%8lu" because "%5lu" > > > > can be easily overflown. > > > > > > > > # cat /sys/fs/bpf/unix > > > > Num RefCount Protocol Flags Type St Inode Path > > > > > > It's totally my OCD, but why the column name is not aligned with > > > values? I mean the "Inode" column. It's left aligned, but values > > > (numbers) are right-aligned? I'd fix that while applying, but I can't > > > apply due to selftests failures, so please take a look. > > > > Ah, honestly, I've felt something strange about the column... will fix it! > > > > > > > > > > > > > > ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer > > > > ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@ > > > > > > > > # cat /proc/net/unix > > > > Num RefCount Protocol Flags Type St Inode Path > > > > ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer > > > > ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@ > > > > > > > > Note that this prog requires the patch ([0]) for LLVM code gen. Thanks to > > > > Yonghong Song for analysing and fixing. > > > > > > > > [0] https://reviews.llvm.org/D107483 > > > > > > > > Signed-off-by: Kuniyuki Iwashima > > > > Acked-by: Yonghong Song > > > > --- > > > > > > This selftests breaks test_progs-no_alu32 ([0], the error log is super > > > long and can freeze browser; it looks like an infinite loop and BPF > > > verifier just keeps reporting it until it runs out of 1mln > > > instructions or something). Please check what's going on there, I > > > can't land it as it is right now. > > > > > > [0] https://github.com/kernel-patches/bpf/runs/3326071112?check_suite_focus=true#step:6:124288 > > > > > > > > > > tools/testing/selftests/bpf/README.rst | 38 +++++++++ > > > > .../selftests/bpf/prog_tests/bpf_iter.c | 16 ++++ > > > > tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++ > > > > .../selftests/bpf/progs/bpf_iter_unix.c | 77 +++++++++++++++++++ > > > > .../selftests/bpf/progs/bpf_tracing_net.h | 4 + > > > > 5 files changed, 143 insertions(+) > > > > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_unix.c > > > > > > > > > > [...] > > > > > > > + /* The name of the abstract UNIX domain socket starts > > > > + * with '\0' and can contain '\0'. The null bytes > > > > + * should be escaped as done in unix_seq_show(). > > > > + */ > > > > + int i, len; > > > > + > > > > > > no_alu32 variant probably isn't happy about using int for this, it > > > probably does << 32, >> 32 dance and loses track of actual value in > > > the loop. You can try using u64 instead. > > > > Sorry, I missed the no_alu32 test. > > Changing int to __u64 fixed the error, thanks! > > > > > > > > > > > + len = unix_sk->addr->len - sizeof(short); > > > > + > > > > + BPF_SEQ_PRINTF(seq, " @"); > > > > + > > > > + /* unix_mkname() tests this upper bound. */ > > > > + if (len < sizeof(struct sockaddr_un)) > > > > + for (i = 1; i < len; i++) > > > > > > if you move above if inside the loop to break out of the loop, does it > > > change how Clang generates code? > > > > > > for (i = 1; i < len i++) { > > > if (i >= sizeof(struct sockaddr_un)) > > > break; > > > BPF_SEQ_PRINTF(...); > > > } > > > > Yes, but there seems little defference. > > Which is preferable? > > > > ---8<--- > > before (for inside if) <- -> after (if inside loop) > > 96: 07 08 00 00 fe ff ff ff r8 += -2 | ; for (i = 1; i < len; i++) { > > ; if (len < sizeof(struct sockaddr_un)) | 97: bf 81 00 00 00 00 00 00 r1 = r8 > > 97: 25 08 10 00 6d 00 00 00 if r8 > 109 goto +16 | 98: 07 01 00 00 fc ff ff ff r1 += -4 > > ; for (i = 1; i < len; i++) | 99: 25 01 12 00 6b 00 00 00 if r1 > 107 goto +18 > > 98: a5 08 0f 00 02 00 00 00 if r8 < 2 goto +15 | 100: 07 08 00 00 fe ff ff ff r8 += -2 > > 99: b7 09 00 00 01 00 00 00 r9 = 1 | 101: b7 09 00 00 01 00 00 00 r9 = 1 > > 100: 05 00 16 00 00 00 00 00 goto +22 | 102: b7 06 00 00 02 00 00 00 r6 = 2 > > | 103: 05 00 17 00 00 00 00 00 goto +23 > > ... > > 111: 85 00 00 00 7e 00 00 00 call 126 | 113: b4 05 00 00 08 00 00 00 w5 = 8 > > ; for (i = 1; i < len; i++) | 114: 85 00 00 00 7e 00 00 00 call 126 > > 112: 07 09 00 00 01 00 00 00 r9 += 1 | ; for (i = 1; i < len; i++) { > > 113: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 | 115: 25 08 02 00 6d 00 00 00 if r8 > 109 goto +2 > > > 116: 07 09 00 00 01 00 00 00 r9 += 1 > > > ; for (i = 1; i < len; i++) { > > > 117: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 > > ---8<--- > > > > Have you tried running the variant I proposed on Clang without > Yonghong's recent fix? I wonder if it works without that fix (not that > there is anything wrong about the fix, but if we can avoid depending > on it, it would be great). It was with the fix. I rebuilt LLVM without the fix, then the if-inside-for code worked well :) There was no transformation from '<' to '!='. I'll drop the change in README and respin with your suggestion soon. ---8<--- ; for (i = 1; i < len; i++) { 97: bf 81 00 00 00 00 00 00 r1 = r8 98: 07 01 00 00 fc ff ff ff r1 += -4 99: 25 01 12 00 6b 00 00 00 if r1 > 107 goto +18 100: 07 08 00 00 fe ff ff ff r8 += -2 101: b7 09 00 00 01 00 00 00 r9 = 1 102: b7 06 00 00 02 00 00 00 r6 = 2 103: 05 00 17 00 00 00 00 00 goto +23 ... ; for (i = 1; i < len; i++) { 115: 25 08 02 00 6d 00 00 00 if r8 > 109 goto +2 116: 07 09 00 00 01 00 00 00 r9 += 1 ; for (i = 1; i < len; i++) { 117: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 ---8<--- > > > > > > > > > > > > > + BPF_SEQ_PRINTF(seq, "%c", > > > > + unix_sk->addr->name->sun_path[i] ?: > > > > + '@'); > > > > + } > > > > + } > > > > + > > > > + BPF_SEQ_PRINTF(seq, "\n"); > > > > + > > > > + return 0; > > > > +} > > > > diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > index 3af0998a0623..eef5646ddb19 100644 > > > > --- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > +++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > @@ -5,6 +5,10 @@ > > > > #define AF_INET 2 > > > > #define AF_INET6 10 > > > > > > > > +#define __SO_ACCEPTCON (1 << 16) > > > > +#define UNIX_HASH_SIZE 256 > > > > +#define UNIX_ABSTRACT(unix_sk) (unix_sk->addr->hash < UNIX_HASH_SIZE) > > > > + > > > > #define SOL_TCP 6 > > > > #define TCP_CONGESTION 13 > > > > #define TCP_CA_NAME_MAX 16 > > > > -- > > > > 2.30.2