From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (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 6432A23D7CE for ; Fri, 7 Aug 2026 00:44:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786063455; cv=none; b=OCSIjtLX0JDZFpCv5jVP5R+zdF6OlXId7AHm6CQGjwPLhpmfL0uAl4V5n+p4mpAnCdepxqSzT2hJdqH3MwCOtRiAiSgGAmaeb4YTxjJ51t+srqIdBMOdS5wJ2lurriCNAzjerRs67R2GcZBVs3NOLUVFuz2mhrl/cF6559tOlwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786063455; c=relaxed/simple; bh=/Cli3Qg9lIea/JErzSXsDrgN00uFn3Tt+AsnDL8c0b0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sooU2K+PtyhXbIdr+xxfqZFFuIEjLu36+eaz1jQYtyC2pycJ1YkK7AJJqEu3TumpU5umJPPPgQQAMK59tGGXw7WlLxZu7HkmxB978VglJIaExwbjpH+QoNU/mQb/hh02NyAi1+kqUUvyHsnBQyi1AEzzrLlUjSBkxczRlcw2B2E= 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=JqLJpgpD; arc=none smtp.client-ip=209.85.210.180 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="JqLJpgpD" Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-8487214ad2bso4349127b3a.1 for ; Thu, 06 Aug 2026 17:44:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786063452; x=1786668252; 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:content-type; bh=byf5De8f/rkIIW6xYCfuIrbPDKZkiq6mBD0098KD+S0=; b=JqLJpgpDSn2vBntBooNLhBp8g/FvPi0RDu6RvnLrBIwguGl6yR8+MJUveuWHjFA3jK wGoh0P/BHRPIR5C1RwhPab+wxRUoP8GVH5t3tNzE3Aqi77XVC/CiUUp1FESU3ubIvrzD qrp+fBc4NN3uZDqKZ7CeSqDIrFekTZLuLkc4xP/ZNoi5eKRCYu/DjcUHVgEHQ69y4sYv zJGqZuxcXBFiBAYX8a1Lzu7Mo8ANd24q6NgIKqC+0tF/hm37djm3WSJj0hzUL1lqIgzA 5BUewhCovJM/Z6V1ajZHaLH20BBFV6YyCc8aa7oy9rWNEwofDJgLwe70okW/K5uOQxZ6 d2tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786063452; x=1786668252; 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:content-type; bh=byf5De8f/rkIIW6xYCfuIrbPDKZkiq6mBD0098KD+S0=; b=jK7vINC9IToUusOU0ywLwYBCUm2MqLvAIGcBo3YnLCQijZbnuks1+ecuU0UHQDk9Hr 6RNhBQWI7Mur+j0KDbxo3PRPt6mt9PTG5RfFImvmtbM/s61iw3JGYVbp9aN31ye9qIUT MMvvl8x9mO3Ir50GLXVfKh9HybnYO6YbCWxcz1w1YnNj5OWbw/Yaq79+V5KPiQgUpP5e vdgR9wGwGPDTOpISxn+Oq8AOyxviFluR0lZGJnRiPFfwR6vhYJsV/1dRATpHHz1vynoN a7KEDSeGv7laGFVgo4OzH1nBpaXxh2AEze5q2q8Ut7wmonQd63Nkud64gIhxz1LWbcmg NpgQ== X-Gm-Message-State: AOJu0Yy499TG6eua0N0+WeqWPp8QK7yl0lpR6R0TgZFnbU6Zy8CRvkzK 5IzzUgX9cn2f7tzixIYOKJyuKNaScdg1YHwG0yE3jkLoLo1Webgn6PX2UaLKcA== X-Gm-Gg: AR+sD10Fi2uDeflg2RIyWXouE0VO8Z2jxtT31mShw43C2/ETwInUD1ZIhx3sEeSwHiN yov0zSkWrywfjt6Pe+/CaVCiv4ucm9eHlXbxZmdlf+SIUP8vr7PjA339Du4dt6U8q7e15gKY2lL cOMEYQAOOKvjfclAB96BxI8GJXli01ulj28ShO2xTlWSCo0h+EV3TQtwR938zL8/a3r5igCTfgk YlcQf7R5uU7CJpZ5OQJDLI9kVrJZac8/kBRMd/285fKG8e6N8GpsyV/1Z8XZGDVBT2cBstNZ3U+ H2pE1BZ9ErHOeOzJ5y2c5vgAQuQNsVhNQJaeOz3lfEjoWHmJLWDC2vZEsSTRFyprLXYHe5cXT1W vxn2ji+aZMbs10uK2K68Odkdz10I6ZhjAAfQs2foi9qSj1HbmjQE84sdjr9m2ZvC66LtCmOV6Bg F6DF3o0kBywaMAbwJxFEB+X3PMUhcPH8G9+NO7s+58QjwdaPUK4eEvSaDZmfNwK5djJpNT4ZKSG s4gEfukikDYKUB+ X-Received: by 2002:a05:6a00:3a12:b0:848:354f:4f8f with SMTP id d2e1a72fcca58-84f2dff3015mr21231822b3a.22.1786063451696; Thu, 06 Aug 2026 17:44:11 -0700 (PDT) Received: from patterson.cs.ubc.ca (patterson.cs.ubc.ca. [198.162.52.65]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84f5a552859sm172922b3a.42.2026.08.06.17.44.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Aug 2026 17:44:11 -0700 (PDT) From: Ning Ding To: bpf@vger.kernel.org Cc: memxor@gmail.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, Ning Ding Subject: [PATCH bpf-next 2/2] selftests/bpf: Test RCU iterator state pruning Date: Thu, 6 Aug 2026 17:43:20 -0700 Message-ID: <20260807004320.134069-3-dingning04@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260807004320.134069-1-dingning04@gmail.com> References: <20260807004320.134069-1-dingning04@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a path where RCU protection reaches zero and then starts again. The iterator is untrusted after this gap and must be rejected. Signed-off-by: Ning Ding --- .../selftests/bpf/progs/iters_task_failure.c | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/iters_task_failure.c b/tools/testing/selftests/bpf/progs/iters_task_failure.c index fe3663dedbe14..bac394ae77f44 100644 --- a/tools/testing/selftests/bpf/progs/iters_task_failure.c +++ b/tools/testing/selftests/bpf/progs/iters_task_failure.c @@ -61,6 +61,33 @@ int BPF_PROG(iter_tasks_lock_and_unlock) return 0; } +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +__failure __msg("expected an RCU CS when using bpf_iter_task_next") +__flag(BPF_F_TEST_STATE_FREQ) +int BPF_PROG(iter_tasks_rcu_state_pruning) +{ + struct bpf_iter_task it; + + bpf_rcu_read_lock(); + bpf_iter_task_new(&it, NULL, BPF_TASK_ITER_ALL_PROCS); + + if (likely(bpf_get_prandom_u32())) { + /* Keep the outer RCU lock active. */ + bpf_rcu_read_lock(); + bpf_rcu_read_unlock(); + } else { + /* Create an unprotected gap. */ + bpf_rcu_read_unlock(); + bpf_rcu_read_lock(); + } + + bpf_iter_task_next(&it); + bpf_iter_task_destroy(&it); + bpf_rcu_read_unlock(); + + return 0; +} + SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") __failure __msg("expected an RCU CS when using bpf_iter_css_next") int BPF_PROG(iter_css_lock_and_unlock) -- 2.43.0