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 7FD3AB644; Sun, 23 Feb 2025 01:26:35 +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=1740273996; cv=none; b=M1dpkvqFoLxRyYYdTdoLD+fmE8jPOmErj1K5IILk0gM79A91/0PVmsxmEBTO18uq5Cgv79Nc1kBTPbtLvxmvSnSJMAgmJNhwc/6v2UKmQ5fX3AOBaUT06CfwjWkqwEUSTz6nQMhB0pefddKsbmQgoryFGme+OA76qGFGM0e5wt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740273996; c=relaxed/simple; bh=cA0Qzsx3di7qLvvFW3YLM+oEEslWRoQzhG7oZuIN6p0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=U0931fv4DgEYawuF6TEeeLmOew7VRjC/JB3F2E7w0GrWKrwE25pbewd1SJjGgf/8BCi9OPrSgQWK0Dxh68gHQUCFaJ7mrj3TCSG74UDSnVPgb7HJ++7/hXQjx1UKd/sLhPKVoRmtr66Zzczwh+2hM/XS3AOqWPWLjbg9/gvLZgs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=cQt8zzWA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="cQt8zzWA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CC80C4CED1; Sun, 23 Feb 2025 01:26:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1740273995; bh=cA0Qzsx3di7qLvvFW3YLM+oEEslWRoQzhG7oZuIN6p0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cQt8zzWAIXhKqpy07ZyA5D+L91WCKexl+QPeRvVlTZzWEFm3Jpdilq108XOP4NrI3 HYMSit7ZTNfSt+iRmJbmYR6L2hy1HQzU5hTb+b9LWs35TpXXbQ7N0two6GjOvjGs3h wlyufZkOnQUJmqpYhRp7fjoXEffp12JDiRrcOP8I= Date: Sat, 22 Feb 2025 17:26:34 -0800 From: Andrew Morton To: Lorenzo Stoakes Cc: "Liam R . Howlett" , Vlastimil Babka , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Brad Spengler Subject: Re: [PATCH] mm: abort vma_modify() on merge out of memory failure Message-Id: <20250222172634.fecb3b5e5f74e310f4a94772@linux-foundation.org> In-Reply-To: <20250222161952.41957-1-lorenzo.stoakes@oracle.com> References: <20250222161952.41957-1-lorenzo.stoakes@oracle.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 22 Feb 2025 16:19:52 +0000 Lorenzo Stoakes wrote: > The remainder of vma_modify() relies upon the vmg state remaining pristine > after a merge attempt. > This patch is against your "mm: simplify vma merge structure and expand comments", presently in mm-unstable. I tweaked things (simple) so it applies to mainline: --- a/mm/vma.c~mm-abort-vma_modify-on-merge-out-of-memory-failure +++ a/mm/vma.c @@ -1509,24 +1509,28 @@ int do_vmi_munmap(struct vma_iterator *v static struct vm_area_struct *vma_modify(struct vma_merge_struct *vmg) { struct vm_area_struct *vma = vmg->vma; + unsigned long start = vmg->start; + unsigned long end = vmg->end; struct vm_area_struct *merged; /* First, try to merge. */ merged = vma_merge_existing_range(vmg); if (merged) return merged; + if (vmg_nomem(vmg)) + return ERR_PTR(-ENOMEM); /* Split any preceding portion of the VMA. */ - if (vma->vm_start < vmg->start) { - int err = split_vma(vmg->vmi, vma, vmg->start, 1); + if (vma->vm_start < start) { + int err = split_vma(vmg->vmi, vma, start, 1); if (err) return ERR_PTR(err); } /* Split any trailing portion of the VMA. */ - if (vma->vm_end > vmg->end) { - int err = split_vma(vmg->vmi, vma, vmg->end, 0); + if (vma->vm_end > end) { + int err = split_vma(vmg->vmi, vma, end, 0); if (err) return ERR_PTR(err); _