From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f180.google.com (mail-pg1-f180.google.com [209.85.215.180]) (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 6B89D34A784 for ; Wed, 22 Oct 2025 12:56:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761137767; cv=none; b=aEk8c+F8McGSDreRubvWbMaRBDpu4tmLaB6O7mAjlHMNGdcCc+jaPW3T3Y/wBr58pYrZfSOXy5ZVhk8BmCojzS5v9aXszxcQ8FcJRQySg7ZpUX0v04MHzSx3FztGD/LnnXnXDI8gPna6Pb5zArIq0ZW1X6pdlSRApkf4ThlWph8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761137767; c=relaxed/simple; bh=55Djqf35I/K3RxxLzdcQP6qMdW/uYAdfSQFf+LthStU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oThAGo0GZxr8OlgOeawSXQhILjnQwDxBJYUaliyAvE/3KXvcJsaenXvFRHOr1PW+jeFBECDnuNmRI7/ZMVMocCMnd5pfHsgLswZDtO8DRDeYpajuwpZaWbGe4c8bWK4XuPCwyKndl6O+9qfIf9gTkgpvlcMmhOfgcLPAlRbz4zQ= 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=BGF9O2Ow; arc=none smtp.client-ip=209.85.215.180 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="BGF9O2Ow" Received: by mail-pg1-f180.google.com with SMTP id 41be03b00d2f7-b67684e2904so4832642a12.2 for ; Wed, 22 Oct 2025 05:56:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761137765; x=1761742565; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=55Djqf35I/K3RxxLzdcQP6qMdW/uYAdfSQFf+LthStU=; b=BGF9O2OwETToO33KLhtkS4GfP1axe7S3jilxDDoEbVe5mh1qiMKOedeftrQgdl/qKK 4KULqF7CSImOTz8PjMH7joKKyO1lkQnZM6dzAnIBX/H54V0c5FfYCq7F8pO53cvVSzWZ k+ZH+MUzc/w5zftoKuM4FCm1w3Wgu3/eslyrv8ihLV/Gvm6iQ0NMI9dDf+iNcQnUlYhf WiREEhy2cB+Hnt/dqS9qmrna+q9to2jjn8X7kNjUeBcsAu2vBaIAXozsoIHVnCClhL2R oAV+NuNIsQ1pP6kgei0r30PnzVyYElvCD51w6vOLHCKRH90eWUKV9lE8FzXe8p6GaH81 nHkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761137765; x=1761742565; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=55Djqf35I/K3RxxLzdcQP6qMdW/uYAdfSQFf+LthStU=; b=TNytVd7gRKAwoy/18wkDdnXH/qqHLdyIOvxt2pY2SnoHN5VcE6obdO9v7IOK1BT0wR 40Iq0VIE3fdbIPRucd2oX3f8i2jfWJaIYvDEGz9D28ZEqLV73ACQuz9Xxu1Zxq/QpUpV 513nyx1x7skLW06/JS+GBzD4F/YogQ+B+pG96s6uyR2/dtlaBPcfzSCdcifqnD2ngsTd g45dxkpwaOzuIh7KLkRRLhFSLjlTA1mX3RLMrf3XqkjpErQ9/DP1Yh3wSYciPPECBDAg 2ECEVUHHNnCk7zDimIWmAbym+ZSs3gX/wHS/Q0FZDOVNzihnJcN0x0JXyB7cfmuoGBmm llZw== X-Forwarded-Encrypted: i=1; AJvYcCUwV5R1WhhXssQiJTJnGI6wW9UkaLFNyYdkluEyiJrQTu3y9+FUKUQM5pd62u/+tr3Km9XkUE5HP6Zl8jw=@vger.kernel.org X-Gm-Message-State: AOJu0Yyky/mH64y12yXIxQ8h9qUcvA6kWZlA2us+cqUaDmeikbXGZAlo +7wJMNNe8nyWT7cQ1cB9nadD4PlGM4nh38Eahc4xenO4V4HzbwKXw3La X-Gm-Gg: ASbGncuFmMhLcSUjCNVmTKXrYrrX+fD1+M31npgw68sHm2euscSaDeQmWglcHIr3fvC Nw6YaXO6mYnbcPQOeeIWv3dpAXyz5rOyknol3lOMUeFAmKMht2DRpKI1UIwEV3xDyZCf+/QU5XM U69fVhmoZgOo/S5TKJv3Ael+WZtyrZPRG/HcsL241/5+A2PVURmhvbKeLZOuvrO+5BOlczUr3CM k/m1+XSKEhpkU73VRJOht/uGQDkvKQmT+H0WPXNZoRlhxAEYouVL7YwxBuid75B3S/wabJPfXRl mHRXhkGwlrKQhqpO1RJ80RP1g8zxyKj8OHz2VKkgMUuLNoopXLRzw2z73yMAHbnhG2pwc1T+2Fd SbTVxCzvFBNyvL7M+9WvHU6kEBWPLaChxOxfpUQtq1AWO/ShmsUSr7y3ylMq5POlTgfXvavN3NE cWJiLdw8kz389hAw== X-Google-Smtp-Source: AGHT+IFAbriApVOx8o8gcjpfk2lo+t2/yibaJf5nwAMFzyuHbx4XWsOEML5CUbO64FfcWtaVnEq9gQ== X-Received: by 2002:a17:902:f78f:b0:290:af0e:1183 with SMTP id d9443c01a7336-290cb65c5e7mr213748355ad.51.1761137764590; Wed, 22 Oct 2025 05:56:04 -0700 (PDT) Received: from [172.20.10.5] ([117.20.154.125]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29247218eafsm137558455ad.101.2025.10.22.05.55.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Oct 2025 05:56:03 -0700 (PDT) Message-ID: <8764fe64-d896-460e-8e0c-cd81667c57b9@gmail.com> Date: Wed, 22 Oct 2025 20:55:55 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v1 1/2] bpf: Add kfuncs for detecting execution context To: Jiayuan Chen , bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20251022113412.352307-1-jiayuan.chen@linux.dev> <20251022113412.352307-2-jiayuan.chen@linux.dev> Content-Language: en-US From: Leon Hwang In-Reply-To: <20251022113412.352307-2-jiayuan.chen@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/10/22 19:33, Jiayuan Chen wrote: > This path introduces several kfuncs to help BPF programs determine their > current execution context. When hooking functions for statistics, we often > need to use current->comm to get the process name. > > However, these hooked functions can be called from either process context > or interrupt context. When called from interrupt context, the current we > obtain may refer to the process that was interrupted, which may not be > what we need. > > These new kfuncs expose APIs that allow users to determine the actual > execution context. Hi Jiayuan, Rather than introducing multiple kfuncs to determine the current execution context, this can already be achieved by using the 'bpf_this_cpu_ptr()' helper to read the underlying preemption count. Please refer to my earlier patch, "selftests/bpf: Introduce experimental bpf_in_interrupt()"[1], which demonstrates this approach. Links: [1] https://lore.kernel.org/bpf/20250903140438.59517-1-leon.hwang@linux.dev/ Thanks, Leon [...]