From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D7FCCCAC59B for ; Tue, 16 Sep 2025 20:08:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2957A8E0006; Tue, 16 Sep 2025 16:08:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 26CF28E0001; Tue, 16 Sep 2025 16:08:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 182238E0006; Tue, 16 Sep 2025 16:08:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 08A478E0001 for ; Tue, 16 Sep 2025 16:08:45 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A1EAE119969 for ; Tue, 16 Sep 2025 20:08:44 +0000 (UTC) X-FDA: 83896201368.19.882512B Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) by imf24.hostedemail.com (Postfix) with ESMTP id ADBF3180011 for ; Tue, 16 Sep 2025 20:08:42 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=qiY9WNsY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf24.hostedemail.com: domain of kaleshsingh@google.com designates 209.85.214.170 as permitted sender) smtp.mailfrom=kaleshsingh@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758053322; a=rsa-sha256; cv=none; b=0+pECoieIezN93G9YMYmnMxwLt+YA/DraScBSONXPypqlKOlxiscw9lN0NdKt0yTsdjO0Z gaaVBT5X3gREEAWqwF8m8Y0Nka8rRAaM+jBgkqAwHRjjGRaUJL2IIIv39mDqv6AdrncE9b IDGW78wI3/3wjXZ2xm0FUwUTSwyOY7s= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=qiY9WNsY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf24.hostedemail.com: domain of kaleshsingh@google.com designates 209.85.214.170 as permitted sender) smtp.mailfrom=kaleshsingh@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758053322; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=x9Lkzd2qHU0WJpoFh7WhpO5uCyrQhSbia0bX3ioP2o8=; b=QP8SuoTKbYGl3LjiJ2DAFLORv9Smy6wU4+bT0pUeJTVNrfdld3frQ6gtkIVyOOf0CAX1Pd 0Ps7RXZ0IW1LcsWc8hEWwiaCCxdsiFG4KH9CLGeI2Qnz7TBYs/gN+fvkxxpcg8dDJIZdbS vGnhfrHK42lGpNXyRgrof1yfy0J++xo= Received: by mail-pl1-f170.google.com with SMTP id d9443c01a7336-2637b6e9149so14585ad.1 for ; Tue, 16 Sep 2025 13:08:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1758053321; x=1758658121; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=x9Lkzd2qHU0WJpoFh7WhpO5uCyrQhSbia0bX3ioP2o8=; b=qiY9WNsYHkYhNXx7LETKXjNO9TFlY6iagmpft8Nl8lF3jTKPCyySGH94ujKHqeeU/w ypAosEWFUURurwU8nq3Y3PMcbQuoz/jpJEXEVRWgoZ/06L5vcRA2H2/iMALDpxF8YlNk 7kLcHpBV6UOxxTx3m3v9pYcSK7FgD/ZtDCEGchEN6T9HbYcjXCaf+vS/wispIfeX8a6d ap0Bp2V/aVxb4kJ2Kc8fRpq2n7A9Fq0lrnCR9pjarD+zoKY3jmmxW/r0UeXe930+BVuK Ee0qyvw5DvekQ1z0oK00wDrqWuZ+I0h3VJCuuJuyDYoZX6UV46dEEoKoLCOzPblCPYPj 93QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758053321; x=1758658121; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=x9Lkzd2qHU0WJpoFh7WhpO5uCyrQhSbia0bX3ioP2o8=; b=Jp7u44cl+zVgs64OtzO/RdWwNY+dy7GcowPTPsCrPXITBVO8gcMRNg12juhmgIQxz7 zKhnaY9UCV6CD5EzdSFKkGNISpq2OnKBiy332gZjs921XxIFzgxezE+NWNxjkZ64307Z xedr7ByJyFfGaTABEoQAKuhyxMEXieHPaogy2fTav4P+DruplEYHRHhU5p7zg/bXWeLT oOfXf6U6LM3WQ0MqEz1uNvQdSavN7Ubi3mP25j1bLlqKtPxODT5kKfNfEBTwQqOOnhsn VdpeTeKeeklMjS0mTZFrIYGjrks8v9l4UQ3Ds9O44g7c10sLaZWCdUu3Z31vFxVIsYUi u8Cw== X-Forwarded-Encrypted: i=1; AJvYcCUALCR2t90PRermM6YHb5rqmevcyx48qs/R0JPRyLmFjHXLD+oYUgAURXVQlPNhWhcC9UtEdMp4oQ==@kvack.org X-Gm-Message-State: AOJu0YymBCYqyFkFbQpc6fAIYl49dP9EHWmx0BmBABl55kiQ3aCxTLPD k6nxnX/rr6Y/yKSfHpYX1aRcZDRzcPozZMad4TmLEZuLWATOSJKI60pIyfw6t2zQN26T1OZeW5R JWM56qXiw9VwNEP/o8YsZu5dSlX+SMODA9q98g8DB X-Gm-Gg: ASbGncvJ4pVAA2vdgAjhrH+1dJtz1IOBboDo6Z4ElDzIl7qL0p2T3tXpWHHPX2rYSZM X7EON5T2ercTek3QLUGxObWovzfdytpYN4/vS7zEHSv3NqZrwrvP14I3MkedyDF/0DH6tc9lrFm qKGk6ChhOU9cU2poGV4lHE5mN0037To/inZRD8f6DXSdrsdkQ0Z+0a+Va7JvKv/QsA3KQRPnz+m FWN27beD6N93T8xtk68I0B9FrEJ8WP9cZasIWCSy8OhP6rpbns= X-Google-Smtp-Source: AGHT+IHB+zIC9M5csK1y9pYvqYGZ9e1a8g5vFs0VSlYor4LBlSAEw+sh6AmBy5K67UD64uBbR+RJ2cXCghc/d1plz/M= X-Received: by 2002:a17:902:d2c9:b0:266:b8a2:f605 with SMTP id d9443c01a7336-26808a2fc00mr122185ad.3.1758053321270; Tue, 16 Sep 2025 13:08:41 -0700 (PDT) MIME-Version: 1.0 References: <20250915163838.631445-1-kaleshsingh@google.com> <20250915163838.631445-8-kaleshsingh@google.com> <20250915194158.472edea5@gandalf.local.home> <20250916115220.4a90c745@batman.local.home> <20250916134833.281e7f8b@gandalf.local.home> <20250916140245.5894a2aa@gandalf.local.home> <20250916145146.046f56a8@batman.local.home> In-Reply-To: <20250916145146.046f56a8@batman.local.home> From: Kalesh Singh Date: Tue, 16 Sep 2025 13:08:29 -0700 X-Gm-Features: AS18NWCVdunjcrUP7tBqVqoMShUmOYlO_Ndh14lC0p7nbWIxXHPwlnQ10YTDEow Message-ID: Subject: Re: [PATCH v2 7/7] mm/tracing: introduce max_vma_count_exceeded trace event To: Steven Rostedt Cc: akpm@linux-foundation.org, minchan@kernel.org, lorenzo.stoakes@oracle.com, david@redhat.com, Liam.Howlett@oracle.com, rppt@kernel.org, pfalcato@suse.de, kernel-team@android.com, android-mm@google.com, Alexander Viro , Christian Brauner , Jan Kara , Kees Cook , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Masami Hiramatsu , Mathieu Desnoyers , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , Jann Horn , Shuah Khan , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: ADBF3180011 X-Stat-Signature: icqc6zxz4qmorapgm3h4nopmf175hkbm X-Rspam-User: X-HE-Tag: 1758053322-511723 X-HE-Meta: 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 z3POO1RV zagdx1IUNjYKSQGUWPnRpR2F/nqNjl/Ky8ihX2oQPgJey72fsFONH7UZ48nTAJlQiAdvpUV180PXZ9vWxD2HAJ8i951Dt3n9+/4Sa/aK7Hu4kpj/c8qhCTq6HLHOLndq6fcwfVtw+6SD+BhAG7Z7SFXD65UsemvBIX1FNjy3JsZYR4FDbppn0Ey2nexf6HPctwwx+RuLgzHAxbggl+KUGbGNiwaQaHfxg+KTh5zh6wGL3rZ+ELK/DyZqg3+ZYUnDF1xMH/C/oQVJfwv3qwikv6DDwOUO+EPnrPuo4LvSmpVBvu52wBiZdBRUranKJltbsuGU8 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 16, 2025 at 11:51=E2=80=AFAM Steven Rostedt wrote: > > On Tue, 16 Sep 2025 11:23:03 -0700 > Kalesh Singh wrote: > > > > When it comes to tracing, you already lost. If it goes into the ring = buffer > > > it's a raw pointer. BPF doesn't use the output of the trace event, so= you > > > are exposing nothing from that. It uses the proto directly. > > > > My understanding is that the BPF tracepoint type uses the trace event > > fields from TP_STRUCT__entry(); whereas the raw tracepoint type has > > access to the proto arguments. Please CMIW: Isn't what we'd be adding > > to the trace buffer is the hashed mm_id value? > > Ah, right. Can't the BPF infrastructure protect against it? > > > > > > > > > Heck, if you enable function tracing, you are exposing every function > > > address it traces via the raw data output. > > > > Right, security doesn't allow compiling CONFIG_FUNCTION_TRACER in > > Android production kernels. > > Does it block all the other trace events that share pointers? > > Like nmi handler tracepoints, x86_fpu tracepoints, page_fault kernel > tracepoint, tasklet tracepoints, cpu hot plug tracepoints, timer > tracepoints, work queue tracepoints, ipi tracepoints, scheduling > tracepoints, locking tracepoints, rcu tracepoints, dma tracepoints, > module tracepoints, xdp tracepoints, filemap tracepoints, page map > tracepoints, vmscan tracepoints, percpu tracepoints, kmem_cache > tracepoints, mmap lock tracepoints, file lock tracepoints, and many > more! (I got tired of looking them up). Hi Steve, I see your point :) I'll use the raw pointer and handle not exposing it from the BPF side. Thanks for discussing. --Kalesh > > Again, are you really protecting anything if this one trace point > hashes the pointer? Most other tracepoints expose this. If BPF can > access a tracepoint entry struct, it can access the raw address and > break KASLR. Thanks, Kalesh > > -- Steve