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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 36E3AC433E2 for ; Mon, 14 Sep 2020 04:59:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1D1C208DB for ; Mon, 14 Sep 2020 04:59:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Om3aDl9W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726028AbgINE7B (ORCPT ); Mon, 14 Sep 2020 00:59:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725995AbgINE66 (ORCPT ); Mon, 14 Sep 2020 00:58:58 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B99DC061787 for ; Sun, 13 Sep 2020 21:58:57 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id c8so16216286edv.5 for ; Sun, 13 Sep 2020 21:58:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=bruhIH4CDHums7UUWVvK8ZwvwKM6vyD/d4MfCflsEtg=; b=Om3aDl9WIviASU808y7ftS1SfffUPIlGspCiwkFK0X80hhlm8kExah6P5oCwh1w62j JSBRPpPzqkXxK45ryxK/SfsUXQIWCU/cXOpiFyQjwZ5JJ/ZK3oCw5GWyci9OgEEQiap2 bOzmsHzb4u8G7Of4XIIXKP9kwvydnwUGuLoTg7oPZijs5AQ5S4WebFLUR44miSDhq+aC GLQfPoj5mTlrhfkc2Lkp2Z0x7QTp7mUJDA+alJjFQ8thea4qVe4wWpCA0FslsJg1kAFg K+2nwPyNTzxZC43iVEw5EI1FDBM4LpMAujbg9LbCTKOVeIYr+tLIofheyhrZHevMXhfM CjOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=bruhIH4CDHums7UUWVvK8ZwvwKM6vyD/d4MfCflsEtg=; b=klfAP3bM4PnirJnasX3omGfeRHCzNkKdDe404ZAuEaqOZi6Bbe3JRoqwwMVRiIyXpr JtlzG0nTf2TG2Qz+bQaFCLBj/WTfrPWFk7xf9BcariQFdgCkXYgompi2XMGwcqk06TU+ 3VlZOoX3yMMYCh1hjY7XsvvT3k7nqSHnEv+fBbW99qXJjZ2sgm0X667mjD33do0HLNqs tWenuj6tsxAklRXvikdQz60iSqaEnaLCedipA+z5EjVJqKoBeA1WvkrvO7NH6xXxVHY8 Kl6DAi3z0SvoiEuOzEhPPEJcQ2jfgidmmibd1Yh+VzdRWA1bfw2WtNT0Gm2TeRnpnptY nqYw== X-Gm-Message-State: AOAM5336a8IdJeN0KhQU9VRMFHDDSMLe0jc1+bhejCpZ7ciN2GF7Mf4T haGXYVgbt6GdvQT7vc4yCwB1QZ189/Xz3Nf212qqBA== X-Google-Smtp-Source: ABdhPJzUl2PIE+E4bdR2k5a/nAFLbfeXoaODUXNbWgYHryIReE2MsJE8Hrq/ShhJGEaZo1TBsmuDvyFioDuUZJE9zSo= X-Received: by 2002:aa7:d606:: with SMTP id c6mr15708061edr.370.1600059535975; Sun, 13 Sep 2020 21:58:55 -0700 (PDT) MIME-Version: 1.0 References: <20200903223332.881541-1-haoluo@google.com> <20200903223332.881541-4-haoluo@google.com> In-Reply-To: From: Hao Luo Date: Sun, 13 Sep 2020 21:58:45 -0700 Message-ID: Subject: Re: [PATCH bpf-next v2 3/6] bpf/selftests: ksyms_btf to test typed ksyms To: Andrii Nakryiko Cc: Networking , bpf , open list , "open list:KERNEL SELFTEST FRAMEWORK" , Shuah Khan , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Quentin Monnet , Steven Rostedt , Ingo Molnar , Andrey Ignatov , Jakub Sitnicki Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Thanks for taking a look, Andrii. On Fri, Sep 4, 2020 at 12:49 PM Andrii Nakryiko wrote: > > On Thu, Sep 3, 2020 at 3:35 PM Hao Luo wrote: > > > > Selftests for typed ksyms. Tests two types of ksyms: one is a struct, > > the other is a plain int. This tests two paths in the kernel. Struct > > ksyms will be converted into PTR_TO_BTF_ID by the verifier while int > > typed ksyms will be converted into PTR_TO_MEM. > > > > Signed-off-by: Hao Luo > > --- > > .../testing/selftests/bpf/prog_tests/ksyms.c | 31 +++------ > > .../selftests/bpf/prog_tests/ksyms_btf.c | 63 +++++++++++++++++++ > > .../selftests/bpf/progs/test_ksyms_btf.c | 23 +++++++ > > tools/testing/selftests/bpf/trace_helpers.c | 26 ++++++++ > > tools/testing/selftests/bpf/trace_helpers.h | 4 ++ > > 5 files changed, 123 insertions(+), 24 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_btf.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf.c > > [...] > > + percpu_datasec = btf__find_by_name_kind(btf, ".data..percpu", > > + BTF_KIND_DATASEC); > > + if (percpu_datasec < 0) { > > + printf("%s:SKIP:no PERCPU DATASEC in kernel btf\n", > > + __func__); > > + test__skip(); > > leaking btf here > > > + return; > > + } > > + > > + skel = test_ksyms_btf__open_and_load(); > > + if (CHECK(!skel, "skel_open", "failed to open and load skeleton\n")) > > here > Oops. Good catches. Will fix. > > + return; > > + > > + err = test_ksyms_btf__attach(skel); > > + if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) > > + goto cleanup; > > + > > + /* trigger tracepoint */ > > + usleep(1); > > + > > + data = skel->data; > > + CHECK(data->out__runqueues != runqueues_addr, "runqueues", > > + "got %llu, exp %llu\n", data->out__runqueues, runqueues_addr); > > + CHECK(data->out__bpf_prog_active != bpf_prog_active_addr, "bpf_prog_active", > > + "got %llu, exp %llu\n", data->out__bpf_prog_active, bpf_prog_active_addr); > > u64 is not %llu on some arches, please cast explicitly to (unsigned long long) > Ack. > > + > > +cleanup: > > ... and here (I suggest to just jump from all those locations here for cleanup) > Makes sense. Will do. > > + test_ksyms_btf__destroy(skel); > > +} > > diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_btf.c b/tools/testing/selftests/bpf/progs/test_ksyms_btf.c > > new file mode 100644 > > index 000000000000..e04e31117f84 > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/progs/test_ksyms_btf.c > > @@ -0,0 +1,23 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* Copyright (c) 2020 Google */ > > + > > +#include "vmlinux.h" > > + > > +#include > > + > > +__u64 out__runqueues = -1; > > +__u64 out__bpf_prog_active = -1; > > this is addresses, not values, so _addr part would make it clearer. > Ack. > > + > > +extern const struct rq runqueues __ksym; /* struct type global var. */ > > +extern const int bpf_prog_active __ksym; /* int type global var. */ > > When we add non-per-CPU kernel variables, I wonder if the fact that we > have both per-CPU and global kernel variables under the same __ksym > section would cause any problems and confusion? It's not clear to me > if we need to have a special __percpu_ksym section or not?.. > Yeah. Totally agree. I thought about this. I think a separate __percpu_ksym attribute is *probably* more clear. Not sure though. How about we introduce a "__percpu_ksym" and make it an alias to "__ksym" for now? If needed, we make an actual section for it in future. > > + > > +SEC("raw_tp/sys_enter") > > +int handler(const void *ctx) > > +{ > > + out__runqueues = (__u64)&runqueues; > > + out__bpf_prog_active = (__u64)&bpf_prog_active; > > + > > + return 0; > > +} > > + > > +char _license[] SEC("license") = "GPL"; > > diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c > > index 4d0e913bbb22..ade555fe8294 100644 > > --- a/tools/testing/selftests/bpf/trace_helpers.c > > +++ b/tools/testing/selftests/bpf/trace_helpers.c > > @@ -90,6 +90,32 @@ long ksym_get_addr(const char *name) > > return 0; > > } > > > > +/* open kallsyms and read symbol addresses on the fly. Without caching all symbols, > > + * this is faster than load + find. */ > > +int kallsyms_find(const char *sym, unsigned long long *addr) > > +{ > > + char type, name[500]; > > + unsigned long long value; > > + int err = 0; > > + FILE *f; > > + > > + f = fopen("/proc/kallsyms", "r"); > > + if (!f) > > + return -ENOENT; > > + > > + while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { > > + if (strcmp(name, sym) == 0) { > > + *addr = value; > > + goto out; > > + } > > + } > > + err = -EINVAL; > > These error codes seem backward to me. If you fail to open > /proc/kallsyms, that's an unexpected and invalid situation, so EINVAL > makes a bit more sense there. But -ENOENT is clearly for cases where > you didn't find what you were looking for, which is exactly this case. > > I thought about it. I used -ENOENT for fopen failure because I found -ENOENT is for the case when a file/directory is not found, which is more reasonable in describing fopen error. But your proposal also makes sense and that is what I originally had. It doesn't sound like a big deal, I can switch the order them in v3. > > + > > +out: > > + fclose(f); > > + return err; > > +} > > + > > void read_trace_pipe(void) > > { > > int trace_fd; > > diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h > > index 25ef597dd03f..f62fdef9e589 100644 > > --- a/tools/testing/selftests/bpf/trace_helpers.h > > +++ b/tools/testing/selftests/bpf/trace_helpers.h > > @@ -12,6 +12,10 @@ struct ksym { > > int load_kallsyms(void); > > struct ksym *ksym_search(long key); > > long ksym_get_addr(const char *name); > > + > > +/* open kallsyms and find addresses on the fly, faster than load + search. */ > > +int kallsyms_find(const char *sym, unsigned long long *addr); > > + > > void read_trace_pipe(void); > > > > #endif > > -- > > 2.28.0.526.ge36021eeef-goog > >