From patchwork Tue Oct 25 18:45:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 13019717 X-Patchwork-Delegate: bpf@iogearbox.net 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 883DBFA373E for ; Tue, 25 Oct 2022 18:46:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232915AbiJYSqT (ORCPT ); Tue, 25 Oct 2022 14:46:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232919AbiJYSqL (ORCPT ); Tue, 25 Oct 2022 14:46:11 -0400 Received: from out2.migadu.com (out2.migadu.com [IPv6:2001:41d0:2:aacc::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66F4373328 for ; Tue, 25 Oct 2022 11:45:49 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1666723548; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=w6PZ4VUfWyonNk0AZVq2qxMIyaU3cM8VoD81Jl31FMQ=; b=kfYnpeAg3s6DsHX82swSxH1kKSxYrD7gK+f+eixB4ihOsLX6iCg7qe9kupKIcBbKeBSr+Y Du2TnM/8CwP1KLNV0zfET033nNvqaVXcMG5ynb+OFrveV2tFnNmJt/byInxIg1e87MI6Rn AJNiTEh0AYHywQVBWfFtw2DP5lO/29o= From: Martin KaFai Lau To: bpf@vger.kernel.org Cc: 'Alexei Starovoitov ' , 'Andrii Nakryiko ' , 'Daniel Borkmann ' , 'Song Liu ' , kernel-team@meta.com Subject: [PATCH bpf-next 5/9] bpf: Add new bpf_task_storage_get proto with no deadlock detection Date: Tue, 25 Oct 2022 11:45:20 -0700 Message-Id: <20221025184524.3526117-6-martin.lau@linux.dev> In-Reply-To: <20221025184524.3526117-1-martin.lau@linux.dev> References: <20221025184524.3526117-1-martin.lau@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Martin KaFai Lau The bpf_lsm and bpf_iter do not recur that will cause a deadlock. The situation is similar to the bpf_pid_task_storage_lookup_elem() which is called from the syscall map_lookup_elem. It does not need deadlock detection. Otherwise, it will cause unnecessary failure when calling the bpf_task_storage_get() helper. This patch adds bpf_task_storage_get proto that does not do deadlock detection. It will be used by bpf_lsm and bpf_iter programs. Signed-off-by: Martin KaFai Lau --- include/linux/bpf.h | 1 + kernel/bpf/bpf_task_storage.c | 28 ++++++++++++++++++++++++++++ kernel/trace/bpf_trace.c | 5 ++++- 3 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index b04fe3f4342e..ef3f98afa45d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2520,6 +2520,7 @@ extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto; extern const struct bpf_func_proto bpf_sock_from_file_proto; extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto; extern const struct bpf_func_proto bpf_task_storage_get_recur_proto; +extern const struct bpf_func_proto bpf_task_storage_get_proto; extern const struct bpf_func_proto bpf_task_storage_delete_recur_proto; extern const struct bpf_func_proto bpf_for_each_map_elem_proto; extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto; diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index bc52bc8b59f7..c3a841be438f 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -269,6 +269,23 @@ BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct return (unsigned long)data; } +/* *gfp_flags* is a hidden argument provided by the verifier */ +BPF_CALL_5(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, + task, void *, value, u64, flags, gfp_t, gfp_flags) +{ + void *data; + + WARN_ON_ONCE(!bpf_rcu_lock_held()); + if (flags & ~BPF_LOCAL_STORAGE_GET_F_CREATE || !task) + return (unsigned long)NULL; + + bpf_task_storage_lock(); + data = __bpf_task_storage_get(map, task, value, flags, + gfp_flags, true); + bpf_task_storage_unlock(); + return (unsigned long)data; +} + BPF_CALL_2(bpf_task_storage_delete_recur, struct bpf_map *, map, struct task_struct *, task) { @@ -342,6 +359,17 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = { .arg4_type = ARG_ANYTHING, }; +const struct bpf_func_proto bpf_task_storage_get_proto = { + .func = bpf_task_storage_get, + .gpl_only = false, + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, + .arg4_type = ARG_ANYTHING, +}; + const struct bpf_func_proto bpf_task_storage_delete_recur_proto = { .func = bpf_task_storage_delete_recur, .gpl_only = false, diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 591caf0eb973..0986c1f0b8fc 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -1488,7 +1489,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_this_cpu_ptr: return &bpf_this_cpu_ptr_proto; case BPF_FUNC_task_storage_get: - return &bpf_task_storage_get_recur_proto; + if (bpf_prog_check_recur(prog)) + return &bpf_task_storage_get_recur_proto; + return &bpf_task_storage_get_proto; case BPF_FUNC_task_storage_delete: return &bpf_task_storage_delete_recur_proto; case BPF_FUNC_for_each_map_elem: