From nobody Wed Oct 1 23:30:04 2025 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (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 3BAEF280A5F for ; Tue, 30 Sep 2025 05:59:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759211987; cv=none; b=UW+Jt57C5nrdaedy7IJZM7hcxynQjDwQcRnfczGJRuFx87vBqNkxi2g27hif7AbIZZBBre59+j4kNgzq+2uCoDd5AGBmd+mqlNBezJZfA9uIwyIZ6BltbcJUe3KtQ6KdgpAuyTFlCg8acH7ZzUvUMWWluQoQSKvVASS6Kf6KLUI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759211987; c=relaxed/simple; bh=CXI0qMvWqpeePDr4xBG9e2uqemr9IpjeVUqDleKN93I=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=a8auq5jjwHviiyPzyIOs48L456qVcVVFvt7KbAMTSObxHrZCYkXwv5i6TptMVO+DiRHH/HqfMENOKV5BGWHDYJCioMWfHExADTmkPxDfPmm8rk6iVWs/YuqmxlTWnnZGcR55XeXKOVC8LOfQ+r+SpX8PCoyGEeY4TWAXxO7mui8= 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=YANox5pF; arc=none smtp.client-ip=209.85.214.172 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="YANox5pF" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-271d1305ad7so71976745ad.2 for ; Mon, 29 Sep 2025 22:59:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759211985; x=1759816785; 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=oOprrquoKlbkEreJojZ4KykFg8G0TswcVk79ghRz+Tk=; b=YANox5pFVE12qunKaUXxgelNvQtoVWW5gGIgclT/DLZg5Ns2oBahLhxY/5yLiw/H0e lXd+/IqPr//ONCHLNyAKFPbHGUUyI/HsQsoxSIB0mA3OO47s3UqZwezuiV/ytRpnC2uQ Vdku5T0A14xpECf6eAvpZvelQTqwnOTeIbZrSu/RiAtV5YywLH2HkawiDbGGa7HFIog/ MkmaAl8au+dfBBg09OoMUsxenMKlzZHS9BFRa78/U0iq90M6s7il8odJGI4OU0Z8WkN7 XEINGVkw3Bj3GSp/CYk0gSWfaVQEGXMhPExSEhCgMi9iz5ScGjiiXE13gWYHRkt2UoJX KZfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759211985; x=1759816785; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=oOprrquoKlbkEreJojZ4KykFg8G0TswcVk79ghRz+Tk=; b=lGyMr/EbQau2nNtuLjyeXebdB01u1FKcP4YRUQIpvmVfzDeTX+AY73Gmt4vnfHhmkq Np+vi8o20KXBD0HdnWPRl0fV5aOpb9t5Jxn5e6coRQ6zPosbAw5cDzupBsGT2eDcwNjm NycihkeRnmWO9NFLY/t+9kKaS5FcECZZTweEwmtTiWqoAsRn8z9qA+89z9EdqPuuXSkP VcaJwXpfEXI1UYBGxWH3E3L49DZa3yr0DVOctxnvy7WtXYfTZfShM61KNkbYoNsHXt+S QUM6W3dTsNLmSpLBHUFD5atQJhsJqUc7tx2Ow/d8ne46DYWud5x5PSyoUCqLnlizlWH9 +zZw== X-Forwarded-Encrypted: i=1; AJvYcCWxUi5IdOWo2fBbdkjuoKLlX0AiZUIS0SCMeJ+AHVuUA3RgaA2dMHapvLBrq+78nimo0uRHSGicHjUqKMM=@vger.kernel.org X-Gm-Message-State: AOJu0YwdYaEyQkN/8CpmzTcZ7QbUNw8GejauPvyfkFdYsI+Df5ugDraj bPH04dfMRr3iH2yhkCoYEXiC+4t9MWJw5zI9q/KBPnn+7KbTJ7dWIfWZ X-Gm-Gg: ASbGncunpnVIPv9cReYz2V6+eXYb3SjmNBuGHBmqyEtXZQkj3rCk4LylDXldVGP0Iz9 tQxO9bugJffEvL7/aSpb6TILs9GpwyRGOIJPMHyo3AlqlxuSF36imYv2zOyxJHzrv7F50eFTgmn YMn2zL03+EAXrQscTjULfa6mNypTNK8eVqry1alfCx/SZ6fGtlkQyu1wXPLZX4uEkVPGzZ6Nd3U yjFsfNZZKhmeH3we5b1/iRMt4AS1NU11mU1seQNl2213fwMfaQBs3ky1J2bDzBQYS2w+gwzdjzk kHtnVRi76LLwk1bMwhSnt6+jgPKDdyBHeZgK5JcOBgme5fgsL/UPt/tdLRsCqE2CCGt5E9ZiYmg CC9jS6Tb0YN9RH9m3r7SfSbtWtN/wxADp7PQm1J94u2RuCjzJjra73FATbIi0ry3WcVRMzqnrBk fYAwpmf8eAIDdLQz+1oeMXyHp8nJmi+BpdeCPUHA== X-Google-Smtp-Source: AGHT+IHaVympRvUhy+mNwqzkCqg8GQH0WHYHPq1npnx2or9ONNHwBhPtVzKfVWrGEP9ED65uKj4qEQ== X-Received: by 2002:a17:903:b83:b0:265:47:a7bd with SMTP id d9443c01a7336-27ed49b802bmr208932635ad.4.1759211985356; Mon, 29 Sep 2025 22:59:45 -0700 (PDT) Received: from localhost.localdomain ([61.171.228.24]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-27ed66d43b8sm148834065ad.9.2025.09.29.22.59.36 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 29 Sep 2025 22:59:44 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, 21cnbao@gmail.com, shakeel.butt@linux.dev, tj@kernel.org, lance.yang@linux.dev, rdunlap@infradead.org Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Yafang Shao Subject: [PATCH v9 mm-new 06/11] bpf: mark mm->owner as __safe_rcu_or_null Date: Tue, 30 Sep 2025 13:58:21 +0800 Message-Id: <20250930055826.9810-7-laoar.shao@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) In-Reply-To: <20250930055826.9810-1-laoar.shao@gmail.com> References: <20250930055826.9810-1-laoar.shao@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" When CONFIG_MEMCG is enabled, we can access mm->owner under RCU. The owner can be NULL. With this change, BPF helpers can safely access mm->owner to retrieve the associated task from the mm. We can then make policy decision based on the task attribute. The typical use case is as follows, bpf_rcu_read_lock(); // rcu lock must be held for rcu trusted field @owner =3D @mm->owner; // mm_struct::owner is rcu trusted or null if (!@owner) goto out; /* Do something based on the task attribute */ out: bpf_rcu_read_unlock(); Suggested-by: Andrii Nakryiko Signed-off-by: Yafang Shao Acked-by: Lorenzo Stoakes --- kernel/bpf/verifier.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c4f69a9e9af6..d400e18ee31e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7123,6 +7123,9 @@ BTF_TYPE_SAFE_RCU(struct cgroup_subsys_state) { /* RCU trusted: these fields are trusted in RCU CS and can be NULL */ BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) { struct file __rcu *exe_file; +#ifdef CONFIG_MEMCG + struct task_struct __rcu *owner; +#endif }; =20 /* skb->sk, req->sk are not RCU protected, but we mark them as such --=20 2.47.3