From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (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 775D1221D9B for ; Thu, 22 May 2025 06:59:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747897147; cv=none; b=Oukxczo+bYc5ju97VDV4x6XsxSVXbzI71X96s0DKgJs4f/VPn0P/nsx1OIGZEPEC7N858t0wa/PApmGKs6bTmOoOxjnCBJH8p+Q9RVR0+Cok5ZgwPGaoeWbY6LS9nzl7vIPyimuX0OdabOkC1ujlfQmyQ/gKU+24nixZXJPMETI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747897147; c=relaxed/simple; bh=hEdJFkIO3gkYUCi5+RF2B0lQFqmJC8q8XaO56pIBmIY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lpB0dkpPVmT4vER9NFgNh66xDmPoouundS6VcQIMBB2CVm/D4yW6l4V1BaEPGaeib3x7vHy7esaIX6N/GheyXVFdlBtkLTNdpJiQLhMuzuZv/R4Ioo+8aiVc8o6E4+QNP4docQq+m2QjMpUF6wfCFDeqbnH554YuiY8ej7hf0P0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b=SCp9qdHP; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="SCp9qdHP" Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-2322bace4ceso41170315ad.2 for ; Wed, 21 May 2025 23:59:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1747897144; x=1748501944; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=S4LjFz6mOQNEL7zonDklRPi1DtpqOZPfCamZxqL1Q0c=; b=SCp9qdHPVi74ClZvLPhcx2IPz+xvcQdFSbkbn1KdIndwhkm7uq7W8zz66fkj6iO+Nv FmPDeuFpRdDZLeKRD4KrwQERS3pPBQNzlp5JzSNx9BmzLSEM2GcOVZaSAijpqQWRNgh4 OrMWg5TwVmsaMCZd9vxAUp6ShUpBX4l+7ezbjpjkUGscnOXRo9nXiMWyTLz9inS2oUmm XzDa4fF+rhN8kzAAwoFw7o3KRduAOmUWuOqWor+M1ASDOfXsKe4dmHvl5zY9+qMbKV9M Ew56qLHiim39W0AV5kn1P680KzFGwoHpBv4RXaNhB8bdLwH9QbOBPeuVM1wiKlZnUtL+ N1OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747897144; x=1748501944; h=content-transfer-encoding:in-reply-to:from: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=S4LjFz6mOQNEL7zonDklRPi1DtpqOZPfCamZxqL1Q0c=; b=UHKSDc/lW2pIJmP2GULWFxHZW/tSIvcdp9KCkJBLSU4rTqvJhdzaWUvmFuVOs6YyI6 YYI6zEXr5pflTrEFP+Yw4gXNVYcTKAwYS5eMj8i2OrPtSZdHorfo2FEsIWgsIor2Rktc 1MbDTIuTbJRtzp7hiWeVX0hUEL6Jq9Sy/s7eh2sr00p60txRKeW40cAR84YbhY8JwFVa RP+KTEFw3KwLwRCRMrhiTPeZYx6SPnOSQbnfBQ7v4yHG4YdrbFBS3cs1fkFfsHL6vC+U 5a2jCIvVT8Bwyjxswc4i18aNB39ZZomjOM6WF2BbKcWsG4wwIggb2ursKnY+jlm3MAdk FXxw== X-Forwarded-Encrypted: i=1; AJvYcCUq+ex6gCyZHHbEhehaMrfaIo3QT003j2Tgb2tf6PsHrGpQkU2qXf2sscdKqjqFZhenisI2DIx410pGlN8=@vger.kernel.org X-Gm-Message-State: AOJu0Yym0NEgEqWJGdgDnw+U+jVvmScR21hTGRwqzBZNYsBrUcKid6+t p6o0snaiarIov7FjCHoklYacKa02x3nb/p6qj3M7Cnqp+6MghaORdRtUQYGa6C/AMwE= X-Gm-Gg: ASbGncvwj9bJxD/nmKbcf9K03lUWWEEgxCEtlPN94O1NlbVaFBEqkWxx1kiJIs6J+eh YWdDWVfRwzYOjbJp7v++0mv7Kd7/rxO8NqeeevpabKKX9win9xQi1v7uoUY9D6VBH/IYvX7lAxL lrB0ohk6j0v8joC3N1mD6ogsO2SUymeJxQPWzbLkOJr8/3dUvRIdVwq+HwHpO75O1zKw4krYwd8 o2wpwbIx2VdBiBYgPQOD64962cSEjNZjSmo+QXp8/baI2RQgx56kUg6KDOs3Fx5YZ8M6XOY5H36 qMnm/RMx2lermcS4njlwiNMEkF/8TXHQz0Hju3MYmG5VSPeG7GHsybWjFy1NQ0UlZtmo8DP/560 = X-Google-Smtp-Source: AGHT+IGp1JwsZ8Ui4zlhII3RRPZ52m9mG0aZy1A/wKlXOSBG5FU1K00VJkoLeuCiJsLgcvYVGZMmxw== X-Received: by 2002:a17:903:1ca:b0:223:2630:6b82 with SMTP id d9443c01a7336-231d43899c1mr346475295ad.10.1747897144452; Wed, 21 May 2025 23:59:04 -0700 (PDT) Received: from [10.68.122.90] ([63.216.146.178]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-231d4ebb0d4sm102734715ad.195.2025.05.21.23.59.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 May 2025 23:59:03 -0700 (PDT) Message-ID: <53518ee0-d5fc-472e-bd67-0be5208b5b77@bytedance.com> Date: Thu, 22 May 2025 14:58:57 +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] mm: fix potential NULL pointer dereference in pagetable_alloc_noprof To: Lorenzo Stoakes , Ye Chey Cc: akpm@linux-foundation.org, david@redhat.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250521124008.36139-1-yechey@ai-sast.com> <206c6dc2-792b-4c73-a922-eebd03864d2c@lucifer.local> <257c094c-522c-48c8-9bc2-70571dfb276f@lucifer.local> From: Qi Zheng In-Reply-To: <257c094c-522c-48c8-9bc2-70571dfb276f@lucifer.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/21/25 8:48 PM, Lorenzo Stoakes wrote: > +cc mailing lists > > Please ensure you always cc these when submitting patches by the way :) > > On Wed, May 21, 2025 at 01:46:48PM +0100, Lorenzo Stoakes wrote: >> On Wed, May 21, 2025 at 08:40:08PM +0800, Ye Chey wrote: >>> The pagetable_alloc_noprof function does not check the return value of >>> alloc_pages_noprof, which could lead to a NULL pointer dereference when >>> memory allocation fails. Add a NULL check to prevent this issue. >>> >>> Signed-off-by: Ye Chey >>> --- >>> include/linux/mm.h | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/include/linux/mm.h b/include/linux/mm.h >>> index bf5520693..9052bb531 100644 >>> --- a/include/linux/mm.h >>> +++ b/include/linux/mm.h >>> @@ -3000,7 +3000,8 @@ static inline bool pagetable_is_reserved(struct ptdesc *pt) >>> static inline struct ptdesc *pagetable_alloc_noprof(gfp_t gfp, unsigned int order) >>> { >>> struct page *page = alloc_pages_noprof(gfp | __GFP_COMP, order); >>> - >>> + if (!page) >>> + return NULL; >>> return page_ptdesc(page); >> >> Doesn't page_ptdesc() just cast the page to the appropriate type? And thus can >> handle it being NULL? Right, no NULL check is needed here. >> >>> } >>> #define pagetable_alloc(...) alloc_hooks(pagetable_alloc_noprof(__VA_ARGS__)) >>> -- >>> 2.44.0 >>>