From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793133150; b=JJMv+meN9ASG/huP8uIHVsj/nLrB4aiwTCnHcfQlyQGQXe27wpo8J5JMTqWvhmkiiENy jeCoNzx9LuS1pQ5Vs7WBjJXYFxu8QnnldfKxLMOa7MXzA1RhtW6XRsdHlgvbIix3taGt+ QveqIIw3tYtBVTe2hbwHgr+vKJ9b3Hgx+wDdbSbC52Kfgijps9RPxQIok6VOsVoRORHAW k+m0r1C0XmECIPq9ouTWPVW9iA+vQSx2yD+RACvSs2TwAxgk8dDo3QsXuIokqim3SJW1c ZPmciiT8MA/gHuDgJxLXO0qL4azbM2jjKAI82xFuQ3uNT8g2GZPgEiLPViEJBk6xYCA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793133150; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=86fhQATGDo+8MDnZqTEUILQavbmG5W/eLVJguZT8p6Y=; b=xXc3tnUoUNa0+9LYCBcEGClOaxVnFwXiLy35NfGhny8ocK4xcxEqKDUqBNdm6pWjZDzy 3ohB9QjSyVvRQvjifBQ7wz69PVIOGzxZ8MUuwqQ0orfLYsjwekh5gPnNPohXQJIthyhtF WpDJpcsHqdb3RlD8D7zNn99ZNKuYNDV1BbwBoxAqqqDN9Gm806vlVZjiGMFbmZ6uVaF2e xHuL+gi8GHjsR10bCbI+um5iNxb8JOCsQBKegLFY5vN9VBd8O1wWZVCtjP9kovpbkOfjd buZ9vVGBQa/mqKmLfjk3y+48KVmbgyCXjQEWVolnyva2kPrO7SXKGWysrDO6czP5ouQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cUUj8rbd; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28C03606A31D; Tue, 27 Oct 2026 20:32:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cUUj8rbd Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D5A11F01825; Tue, 27 Oct 2026 20:32:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793133150; bh=86fhQATGDo+8MDnZqTEUILQavbmG5W/eLVJguZT8p6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=cUUj8rbdB8sxeJkMuDL4RCOdrYbrRplzvevKwnxFuwaEcH7HP+ENffudf2T0mpEpv 5IgYZPx4U8OILjqSgrQVM2ZVtEuU+s+iUCRqr37O0SlFEfCwYP6WH8sUr54mzsCt1s iMf6J0wk9xYuuAD3vV+C40mhUS8iHT1njIORZz73KfNOXA2HaiIMPxjzwaUpjzGq0a +HDzAe6Y83Ik9oMrM+EDzTEENc7lTwdaNWApON+amLO666KTk6vgqAwdt/I26Z5K2e tnFRDkmrRt4vDlqitIfQMOzf4AtEOnF0EKCtlUHfO8gpTP2ZD2//SXJTbcFDzwJNgN ttZ0nsquNOB0g== Date: Tue, 27 Oct 2026 20:32:28 +0000 From: Harry Yoo To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Josef Bacik Subject: Re: [PATCH 43/46] mm/vma: don't leak the charge for stack growth Message-ID: References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-43-6f74bec9a5bb@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027-fixes_core-v1-43-6f74bec9a5bb@kernel.org> On Tue, Oct 27, 2026 at 12:18:03AM +0100, David Hildenbrand (Arm) wrote: > acct_stack_growth() charges stack expansion even without VM_ACCOUNT. > This can happen for read-only or MAP_NORESERVE mappings created with > MAP_GROWSDOWN. Unmapping these VMAs does not release the charge, leaking > Committed_AS. > > Only check and charge growth for VM_ACCOUNT VMAs, matching mremap(). > Unaccounted growth skips the overcommit check while remaining subject > to the other stack-growth limits. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Cc: stable@vger.kernel.org > Reported-by: Josef Bacik > Reviewed-by: Lorenzo Stoakes (ARM) > Signed-off-by: David Hildenbrand (Arm) > --- Looks good to me, Reviewed-by: Harry Yoo (Meta) Maybe worth having a warning when it's accounting w/o VMA_ACCOUNT_BIT or let those helpers skip when there's no VMA_ACCOUNT_BIT set... -- Cheers, Harry / Hyeonggon