From patchwork Wed Oct 18 06:03:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13426389 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA1F95696 for ; Wed, 18 Oct 2023 06:03:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="HHNeyvaA" Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 113C1C6 for ; Tue, 17 Oct 2023 23:03:31 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id 41be03b00d2f7-53fa455cd94so4322563a12.2 for ; Tue, 17 Oct 2023 23:03:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697609010; x=1698213810; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=0Yny8ItW46OK7rUv9Oe3PkxnQdP3AuhNQzFdhCDPWrw=; b=HHNeyvaAqVXVS9NmyigqoDi5uH1O7JqrV8Y8V+fa+zReOWjpl0rZLTKqj/iKXBIl7U t6+Hha7X+TDRgmWXvr6kEJCnZ/HbQEQS5DO0yiXxojSbQtCwmX59aZRh/AGxucG0Koft qE3Ivr4+EBXHJSYYMXvPQ+qfMRfj11wsqFbMQAnTPhZUadmyfNuKFiVRu9XW3t5rNGXg /rbRUJUYQr2CQ6Nz/kdrpkQYE5ZaJIia8VMC26Tmrh/1xHTiXtLKuNYrRBs/3Ycc2eaX grmo6EWiGiXaHzqnktLClTZT49GImFsJIL97nZxzbsrzvMkTHAU5hREvFnCV02VCo9R7 U6Jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697609010; x=1698213810; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=0Yny8ItW46OK7rUv9Oe3PkxnQdP3AuhNQzFdhCDPWrw=; b=MRI+VMFrEK2PFGTDu7aySTPQIjYWmfDwmVfX12wR/YbcyxveOi64LjoBjBDS77hsu9 oR3ki5OUvLkOPckqGOOb83vc4DbL1JQLDx7Wwzryu4wAOVwNSrFnUJATsAcQQiAS3mw2 HjAR4kKuQmQV739VnKJXPmp42aK9TWeMPRTo72WBfCm7qfqAz7LD30kNK9cLtmRSJCQC nFI8f0hsTwe+VWRLUNe9GGFJVl3sNuiQ24eokkEqxXMsXdonvzUVNwopdTAnvq8aEt2a 8jjVFLL2/+H43qFNCyPCVx9BMTMTVaMWZ2HXnA7ONCKENfOdodv4lTpoj1RA78zYdCWA Xe9Q== X-Gm-Message-State: AOJu0YyONSl3c3nISrOimN2+30qS+M4Kg2hU+0wGDBApOJrzEN4aBMEl rMLSOnIaYKpy2n9W9AIZA/3T3D3YqcAau3xIabY= X-Google-Smtp-Source: AGHT+IGe95d5DKx7zmaI9y+7E0QfJZkVBNGoB7gD+WPxeVJcHPdZLRFbaqH+YrNQtVF9DIgmEEUVqg== X-Received: by 2002:a05:6a20:3953:b0:155:5c28:ea74 with SMTP id r19-20020a056a20395300b001555c28ea74mr4518225pzg.12.1697609010100; Tue, 17 Oct 2023 23:03:30 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.40]) by smtp.gmail.com with ESMTPSA id b14-20020a17090acc0e00b00276cb03a0e9sm505782pju.46.2023.10.17.23.03.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Oct 2023 23:03:29 -0700 (PDT) From: Chuyi Zhou To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, tj@kernel.org, linux-kernel@vger.kernel.org, Chuyi Zhou Subject: [PATCH bpf-next v6 0/8] Add Open-coded task, css_task and css iters Date: Wed, 18 Oct 2023 14:03:10 +0800 Message-Id: <20231018060318.105524-1-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net This is version 6 of task, css_task and css iters support. --- Changelog --- v5 -> v6: Patch #3: * In bpf_iter_task_next, return pos rather than goto out. (Andrii) Patch #2, #3, #4: * Add the missing __diag_ignore_all to avoid kernel build warning Patch #5, #6, #7: * Add Andrii's ack Patch #8: * In BPF prog iter_css_task_for_each, return -EPERM rather than 0, and ensure stack_mprotect() in iters.c not success. If not, it would cause the subsequent 'test_lsm' fail, since the 'is_stack' check in test_int_hook(lsm.c) would not be guaranteed. (https://github.com/kernel-patches/bpf/actions/runs/6489662214/job/17624665086?pr=5790) v4 -> v5:https://lore.kernel.org/lkml/20231007124522.34834-1-zhouchuyi@bytedance.com/ Patch 3~4: * Relax the BUILD_BUG_ON check in bpf_iter_task_new and bpf_iter_css_new to avoid netdev/build_32bit CI error. (https://netdev.bots.linux.dev/static/nipa/790929/13412333/build_32bit/stderr) Patch 8: * Initialize skel pointer to fix the LLVM-16 build CI error (https://github.com/kernel-patches/bpf/actions/runs/6462875618/job/17545170863) v3 -> v4:https://lore.kernel.org/all/20230925105552.817513-1-zhouchuyi@bytedance.com/ * Address all the comments from Andrii in patch-3 ~ patch-6 * Collect Tejun's ack * Add a extra patch to rename bpf_iter_task.c to bpf_iter_tasks.c * Seperate three BPF program files for selftests (iters_task.c iters_css_task.c iters_css.c) v2 -> v3:https://lore.kernel.org/lkml/20230912070149.969939-1-zhouchuyi@bytedance.com/ Patch 1 (cgroup: Prepare for using css_task_iter_*() in BPF) * Add tj's ack and Alexei's suggest-by. Patch 2 (bpf: Introduce css_task open-coded iterator kfuncs) * Use bpf_mem_alloc/bpf_mem_free rather than kzalloc() * Add KF_TRUSTED_ARGS for bpf_iter_css_task_new (Alexei) * Move bpf_iter_css_task's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_css_task_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 3 (Introduce task open coded iterator kfuncs) * Change th API design keep consistent with SEC("iter/task"), support iterating all threads(BPF_TASK_ITERATE_ALL) and threads of a specific task (BPF_TASK_ITERATE_THREAD).（Andrii) * Move bpf_iter_task's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_task_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 4 (Introduce css open-coded iterator kfuncs) * Change th API design keep consistent with cgroup_iters, reuse BPF_CGROUP_ITER_DESCENDANTS_PRE/BPF_CGROUP_ITER_DESCENDANTS_POST /BPF_CGROUP_ITER_ANCESTORS_UP(Andrii) * Add KF_TRUSTED_ARGS for bpf_iter_css_new * Move bpf_iter_css's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_css_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 5 (teach the verifier to enforce css_iter and task_iter in RCU CS) * Add KF flag KF_RCU_PROTECTED to maintain kfuncs which need RCU CS.(Andrii) * Consider STACK_ITER when using bpf_for_each_spilled_reg. Patch 6 (Let bpf_iter_task_new accept null task ptr) * Add this extra patch to let bpf_iter_task_new accept a 'nullable' * task pointer(Andrii) Patch 7 (selftests/bpf: Add tests for open-coded task and css iter) * Add failure testcase(Alexei) Changes from v1(https://lore.kernel.org/lkml/20230827072057.1591929-1-zhouchuyi@bytedance.com/): - Add a pre-patch to make some preparations before supporting css_task iters.(Alexei) - Add an allowlist for css_task iters(Alexei) - Let bpf progs do explicit bpf_rcu_read_lock() when using process iters and css_descendant iters.(Alexei) --------------------- In some BPF usage scenarios, it will be useful to iterate the process and css directly in the BPF program. One of the expected scenarios is customizable OOM victim selection via BPF[1]. Inspired by Dave's task_vma iter[2], this patchset adds three types of open-coded iterator kfuncs: 1. bpf_task_iters. It can be used to 1) iterate all process in the system, like for_each_forcess() in kernel. 2) iterate all threads in the system. 3) iterate all threads of a specific task 2. bpf_css_iters. It works like css_task_iter_{start, next, end} and would be used to iterating tasks/threads under a css. 3. css_iters. It works like css_next_descendant_{pre, post} to iterating all descendant css. BPF programs can use these kfuncs directly or through bpf_for_each macro. link[1]: https://lore.kernel.org/lkml/20230810081319.65668-1-zhouchuyi@bytedance.com/ link[2]: https://lore.kernel.org/all/20230810183513.684836-1-davemarchevsky@fb.com/ Chuyi Zhou (8): cgroup: Prepare for using css_task_iter_*() in BPF bpf: Introduce css_task open-coded iterator kfuncs bpf: Introduce task open coded iterator kfuncs bpf: Introduce css open-coded iterator kfuncs bpf: teach the verifier to enforce css_iter and task_iter in RCU CS bpf: Let bpf_iter_task_new accept null task ptr selftests/bpf: rename bpf_iter_task.c to bpf_iter_tasks.c selftests/bpf: Add tests for open-coded task and css iter include/linux/bpf_verifier.h | 19 ++- include/linux/btf.h | 1 + include/linux/cgroup.h | 12 +- kernel/bpf/cgroup_iter.c | 65 ++++++++ kernel/bpf/helpers.c | 9 ++ kernel/bpf/task_iter.c | 151 ++++++++++++++++++ kernel/bpf/verifier.c | 86 ++++++++-- kernel/cgroup/cgroup.c | 18 ++- .../testing/selftests/bpf/bpf_experimental.h | 19 +++ .../selftests/bpf/prog_tests/bpf_iter.c | 18 +-- .../testing/selftests/bpf/prog_tests/iters.c | 150 +++++++++++++++++ .../{bpf_iter_task.c => bpf_iter_tasks.c} | 0 tools/testing/selftests/bpf/progs/iters_css.c | 72 +++++++++ .../selftests/bpf/progs/iters_css_task.c | 47 ++++++ .../testing/selftests/bpf/progs/iters_task.c | 41 +++++ .../selftests/bpf/progs/iters_task_failure.c | 105 ++++++++++++ 16 files changed, 771 insertions(+), 42 deletions(-) rename tools/testing/selftests/bpf/progs/{bpf_iter_task.c => bpf_iter_tasks.c} (100%) create mode 100644 tools/testing/selftests/bpf/progs/iters_css.c create mode 100644 tools/testing/selftests/bpf/progs/iters_css_task.c create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c create mode 100644 tools/testing/selftests/bpf/progs/iters_task_failure.c