From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DDD1439B978 for ; Tue, 21 Apr 2026 08:55:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776761723; cv=none; b=k4BtcbtxpKcsdoZdjR9/Fl/kwnzq4Ix5ZN1OvuIJf+5AIr6FcIDBDzmGux6Xg0xIGdqNXTr/Mo2N2csz2SPkWVniA9QjQoaZ0caE1m1FPSY8GTOB/XT4gHKbFez7Pf6zdT2PjE0nbx5KV/a/ZziUYui/DJRyhH9UC1vFsIenWZw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776761723; c=relaxed/simple; bh=MbGHGAUZtPobdHB5+R/2WAvW/vSfdXeJK/09XVNsJvs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MT4mkrqgurllbDwbTr2j/YTn4U5KtHWskWOb4IVCilRNPyh5Ck841+UOBUGpNyolRD3Zy9Zm89/ECiEWKPIE6+uclrmqAwh+NVWzcR4Gnd/Gw+9XiAl4dSzUBYeIzykOlp32aLszp8IVVs1oyJK3qLJXXJaQJ9bMyjwlV6/4W88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=caj96Jq3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="caj96Jq3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A742BC2BCB5; Tue, 21 Apr 2026 08:55:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776761723; bh=MbGHGAUZtPobdHB5+R/2WAvW/vSfdXeJK/09XVNsJvs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=caj96Jq3tixEPXQiTuBCIJBcoZPlevATza9ys2V6wdv+Ih40LQeRpmFX2v/Uux6Sw O9YwDqIW7CutMQUeQvIH6lYEcDAEarOrs9lz1f8o2LpAg72cmOO77lgMdpAMGKsdOh XXHklKVF9y06MYdJhfclQa6Ke9+Xlvi83geMJjECKsqnnpUFEwVBsUrs/CKwoi/78k akkrKK1CaBeGVT3sKceFmv3ahNhiaB22YmMMF2Tg52AOjvEB5oz6Jz6Zu5oTE2Oqsu mqnSTClNEKPFuEwcodOO/quWhTSperWMjWqffYDgX6b636+4vnzmUK9wjEt2xJrLvr v5aIk45OavkkQ== Message-ID: <2f4a1999-fbd2-4cbb-8062-5574d3c1e7ce@kernel.org> Date: Tue, 21 Apr 2026 10:55:16 +0200 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] mm: handle potential NULL return from anon_vma_name_reuse() To: Ye Liu , Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes Cc: Ye Liu , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260421085056.26033-1-ye.liu@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260421085056.26033-1-ye.liu@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/21/26 10:50, Ye Liu wrote: > From: Ye Liu > > The anon_vma_name_reuse() function may return NULL if memory allocation > fails in anon_vma_name_alloc(). Currently, callers dup_anon_vma_name() > and replace_anon_vma_name() do not check the return value, which could > lead to NULL pointer dereferences. When, where? If we set vma->anon_name = NULL, it just looks like there is no anon VMA, or what am I missing? > > This patch adds proper error handling: > - In dup_anon_vma_name(), if anon_vma_name_reuse() returns NULL, emit a > warning via WARN_ON_ONCE(1) since this is an unexpected condition. > - In replace_anon_vma_name(), return -ENOMEM to propagate the allocation > failure to the caller. > > These changes improve robustness against memory allocation failures. > > Signed-off-by: Ye Liu > --- > include/linux/mm_inline.h | 12 +++++++++--- > mm/madvise.c | 7 ++++++- > 2 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h > index a171070e15f0..9bbaf8287806 100644 > --- a/include/linux/mm_inline.h > +++ b/include/linux/mm_inline.h > @@ -421,9 +421,15 @@ static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma, > struct vm_area_struct *new_vma) > { > struct anon_vma_name *anon_name = anon_vma_name(orig_vma); > - > - if (anon_name) > - new_vma->anon_name = anon_vma_name_reuse(anon_name); > + struct anon_vma_name *new_name; > + > + if (anon_name) { > + new_name = anon_vma_name_reuse(anon_name); > + if (new_name) > + new_vma->anon_name = new_name; > + else > + WARN_ON_ONCE(1); Triggering a warning when an allocation fails? Certainly not. -- Cheers, David