From nobody Sun Feb 8 17:36:30 2026 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 95C9A287263 for ; Sun, 8 Feb 2026 02:49:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770518974; cv=none; b=m+LdNQ9TQJu6/1RmKCJeLlanPJhPJ/wd4iF06HQlGHrUMVe1mJ6NuMxftyKgnon72qSQ/Wom7cG9tHU4RpZ2vg0p8bxOAR1VzJDqroAtyK/ks2N/8RFyulQIPZ9JVDPW+OS+36pT7Dqo9Hxjsl0++Aj4JFFgXzy2PKtBgyfDqsU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770518974; c=relaxed/simple; bh=HyK27wmWpvNXYaxDWFYLGlawGlu1xGVw5LGjGH+YMNc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EFLfM5+Z7eiHDAbZaYbYVpKhm9Zt3gLXoFSZ/s9dG2VmVrS99tTVzSqTTkoeamFxW+wnY07qEZrH1O49JOfPlrrcocoiTcZaf8sJXhXg6yBu/BwBe1Fmzsjnp3ipXcYvH9lxdiqolyBmJU4KNTCoJSmRs/6MM3OfnHgISBdZvxg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hGRjvio8; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hGRjvio8" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-2a9042df9a2so10321285ad.2 for ; Sat, 07 Feb 2026 18:49:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770518974; x=1771123774; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=dxmSnsFITlfMEb8wiQ5FrXf9I6S3N1VemzQNQpL3mIU=; b=hGRjvio8jOeJ5hu9lMkTJKy6KApSwf1Js+LUGFx9RpiAnXxxxZQ9Krm+432qf0cGEM OlAZp5Y7wHP7Lre0doV0t2bR8Su8qSfiGPW9BuErkkHWRHtlIcbwHKwsuGLKmrNH8rWB 1kk09USWu6lSBo4VOkQr3GAMqmexow6dKG06LMhEcZfWlZRf9EVmiGxkXm7TlIjLA+RB H/9kl5+VxUJptmEee/4HQVSm1ZalVLpqHiTbVieXNIu2PXO21NCukbSB3E2dm6kfR0jI MmP595Un365Y9jHOnzKFvh/ESI8vH+zjZWgInpuYLNP1EjB/k6imk9lKZRSLprz1UJBb uUtA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770518974; x=1771123774; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=dxmSnsFITlfMEb8wiQ5FrXf9I6S3N1VemzQNQpL3mIU=; b=iF+6VPs4xKRirNVomqgOkpbVK0OsMRimP+IbiDjUQwsSg24DMxZcolZlJBxB8k+jPp dQLa90IADuj/PPC7kYvHXFWOBRVtcMtXTTeFZrYGA3SXEniOWkJaPvt8ROgNn2vI1XAH RMJRmy44sFj1WAq0f91gFqrHreGcCDzt8q1tCEKUt7Z48vWBKa76G9vDvRNZGYIlJ1Uo XlKj/LqLLkETfCM2SbWX9t8aP+u8X2S/rYhDhnV60E5FG9dkh3J52wcQS1HY0xBneRkL qQMg6ri/rxHUyMckhhTMNTABYXEMR9ogTl5NM2W7bZZ9iBpiilhMcSFGxJc8KtFz3aZU lnxA== X-Gm-Message-State: AOJu0Yz8a8Geh0q3r9lAbjgxGGSiNK3Clb0fBGtkobx1NsG7XO+F0TL0 EyjvZ24xv90X9V8/g0ZXsVRfe/TH+DXIrkvelQ6m/yFB6filHZfawNnw X-Gm-Gg: AZuq6aIf0ddruMHuH2WkW045nHF1jAVMbRlkywF+5SRx5qaC+Jb14kLkXLSgAhrt8nW 7s+7oa2nCRcbJxuTd7l/C32e2c67ObOw7tJAWoxstiB9ktHZe/hl+JbcW0XRHc+Qe/kK7RcmSVa RDgYUqfKNe2qjpFtGQVAoLqNF4G13XyAcjpdiNkgeFObokH+CBKecqtaIfXticSltDIYGaNER3c mY9a0fo5tfNnJupo1cRz0twDGk2V0utJpW3dZhVIiPmzQLkSVW3VmpUUexlGvDjoWm6SALcMEIu 8wDdzeIp7IowpBNRHIWC1sH78P9o1zrj/2127I6ueTVdyIYQuF+A2bTELSdsHb95qIrMFaCdZZq xfk826HFnR0zc6KsyLxuQAL08sfKLlRSGQ5TCCIbXIBJeg65ScA1RJsj4lGIlGWSMKIchs9dO00 CjFBkcVx/ZOVOORAMsngm1mJu7pIAY1/jvPlSsstDt X-Received: by 2002:a17:903:2412:b0:2a9:5e25:46f6 with SMTP id d9443c01a7336-2a95e255c83mr57329225ad.17.1770518973927; Sat, 07 Feb 2026 18:49:33 -0800 (PST) Received: from localhost.localdomain ([113.218.252.53]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a9521b9f5esm67194715ad.51.2026.02.07.18.49.23 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sat, 07 Feb 2026 18:49:33 -0800 (PST) From: Chengkaitao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, yangfeng@kylinos.cn, alexei.starovoitov@gmail.com Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Kaitao Cheng Subject: [PATCH v6 3/5] selftests/bpf: Add supplementary tests for bpf_kptr_xchg Date: Sun, 8 Feb 2026 10:48:44 +0800 Message-ID: <20260208024846.18653-4-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260208024846.18653-1-pilgrimtao@gmail.com> References: <20260208024846.18653-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Kaitao Cheng 1. Allow using bpf_kptr_xchg while holding a lock. 2. When the rb_node contains a __kptr pointer, we do not need to perform a remove-read-add operation. This patch implements the following workflow: 1. Construct a rbtree with 16 elements. 2. Traverse the rbtree, locate the kptr pointer in the target node, and read the content pointed to by the pointer. 3. Remove all nodes from the rbtree. Signed-off-by: Kaitao Cheng Signed-off-by: Feng Yang --- .../testing/selftests/bpf/prog_tests/rbtree.c | 6 + tools/testing/selftests/bpf/progs/bpf_misc.h | 4 + .../selftests/bpf/progs/rbtree_search_kptr.c | 167 ++++++++++++++++++ 3 files changed, 177 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/rbtree_search_kptr.c diff --git a/tools/testing/selftests/bpf/prog_tests/rbtree.c b/tools/testin= g/selftests/bpf/prog_tests/rbtree.c index d8f3d7a45fe9..a854fb38e418 100644 --- a/tools/testing/selftests/bpf/prog_tests/rbtree.c +++ b/tools/testing/selftests/bpf/prog_tests/rbtree.c @@ -9,6 +9,7 @@ #include "rbtree_btf_fail__wrong_node_type.skel.h" #include "rbtree_btf_fail__add_wrong_type.skel.h" #include "rbtree_search.skel.h" +#include "rbtree_search_kptr.skel.h" =20 static void test_rbtree_add_nodes(void) { @@ -193,3 +194,8 @@ void test_rbtree_search(void) { RUN_TESTS(rbtree_search); } + +void test_rbtree_search_kptr(void) +{ + RUN_TESTS(rbtree_search_kptr); +} diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/s= elftests/bpf/progs/bpf_misc.h index c9bfbe1bafc1..0904fe14ad1d 100644 --- a/tools/testing/selftests/bpf/progs/bpf_misc.h +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h @@ -188,6 +188,10 @@ #define POINTER_VALUE 0xbadcafe #define TEST_DATA_LEN 64 =20 +#ifndef __aligned +#define __aligned(x) __attribute__((aligned(x))) +#endif + #ifndef __used #define __used __attribute__((used)) #endif diff --git a/tools/testing/selftests/bpf/progs/rbtree_search_kptr.c b/tools= /testing/selftests/bpf/progs/rbtree_search_kptr.c new file mode 100644 index 000000000000..069fc64b0167 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/rbtree_search_kptr.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 KylinSoft Corporation. */ + +#include +#include +#include "bpf_misc.h" +#include "bpf_experimental.h" + +#define NR_NODES 16 + +struct node_data { + int data; +}; + +struct tree_node { + struct bpf_rb_node node; + u64 key; + struct node_data __kptr * node_data; +}; + +#define private(name) SEC(".data." #name) __hidden __aligned(8) + +private(A) struct bpf_rb_root root __contains(tree_node, node); +private(A) struct bpf_spin_lock lock; + +static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b) +{ + struct tree_node *node_a, *node_b; + + node_a =3D container_of(a, struct tree_node, node); + node_b =3D container_of(b, struct tree_node, node); + + return node_a->key < node_b->key; +} + +SEC("syscall") +__retval(0) +long rbtree_search_kptr(void *ctx) +{ + struct tree_node *tnode; + struct bpf_rb_node *rb_n; + struct node_data __kptr * node_data; + int lookup_key =3D NR_NODES / 2; + int lookup_data =3D NR_NODES / 2; + int i, data, ret =3D 0; + + for (i =3D 0; i < NR_NODES && can_loop; i++) { + tnode =3D bpf_obj_new(typeof(*tnode)); + if (!tnode) + return __LINE__; + + node_data =3D bpf_obj_new(typeof(*node_data)); + if (!node_data) { + bpf_obj_drop(tnode); + return __LINE__; + } + + tnode->key =3D i; + node_data->data =3D i; + + node_data =3D bpf_kptr_xchg(&tnode->node_data, node_data); + if (node_data) + bpf_obj_drop(node_data); + + bpf_spin_lock(&lock); + bpf_rbtree_add(&root, &tnode->node, less); + bpf_spin_unlock(&lock); + } + + bpf_spin_lock(&lock); + rb_n =3D bpf_rbtree_root(&root); + while (rb_n && can_loop) { + tnode =3D container_of(rb_n, struct tree_node, node); + node_data =3D bpf_kptr_xchg(&tnode->node_data, NULL); + if (!node_data) { + ret =3D __LINE__; + goto fail; + } + + data =3D node_data->data; + node_data =3D bpf_kptr_xchg(&tnode->node_data, node_data); + if (node_data) { + bpf_spin_unlock(&lock); + bpf_obj_drop(node_data); + return __LINE__; + } + + if (lookup_key =3D=3D tnode->key) { + if (data =3D=3D lookup_data) + break; + + ret =3D __LINE__; + goto fail; + } + + if (lookup_key < tnode->key) + rb_n =3D bpf_rbtree_left(&root, rb_n); + else + rb_n =3D bpf_rbtree_right(&root, rb_n); + } + bpf_spin_unlock(&lock); + + while (can_loop) { + bpf_spin_lock(&lock); + rb_n =3D bpf_rbtree_first(&root); + if (!rb_n) { + bpf_spin_unlock(&lock); + return 0; + } + + rb_n =3D bpf_rbtree_remove(&root, rb_n); + if (!rb_n) { + ret =3D __LINE__; + goto fail; + } + bpf_spin_unlock(&lock); + + tnode =3D container_of(rb_n, struct tree_node, node); + + node_data =3D bpf_kptr_xchg(&tnode->node_data, NULL); + if (node_data) + bpf_obj_drop(node_data); + + bpf_obj_drop(tnode); + } + + return 0; +fail: + bpf_spin_unlock(&lock); + return ret; +} + + +SEC("syscall") +__failure __msg("R1 type=3Dscalar expected=3Dmap_value, ptr_, ptr_") +long non_own_ref_kptr_xchg_no_lock(void *ctx) +{ + struct tree_node *tnode; + struct bpf_rb_node *rb_n; + struct node_data __kptr * node_data; + int data; + + bpf_spin_lock(&lock); + rb_n =3D bpf_rbtree_first(&root); + if (!rb_n) { + bpf_spin_unlock(&lock); + return __LINE__; + } + bpf_spin_unlock(&lock); + + tnode =3D container_of(rb_n, struct tree_node, node); + node_data =3D bpf_kptr_xchg(&tnode->node_data, NULL); + if (!node_data) + return __LINE__; + + data =3D node_data->data; + if (data < 0) + return __LINE__; + + node_data =3D bpf_kptr_xchg(&tnode->node_data, node_data); + if (node_data) + return __LINE__; + + return 0; +} + +char _license[] SEC("license") =3D "GPL"; --=20 2.50.1 (Apple Git-155)