From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELvSYY6FlA9Mo9Lc7LqgXh7GysqJ4aR5x7QXWNFdpP5lZDrLKURNQ4FrPndbsxKt1eq8Q32+ ARC-Seal: i=1; a=rsa-sha256; t=1520961614; cv=none; d=google.com; s=arc-20160816; b=HlJRpcRO6CdztYQclGIXzIZuGocNEzSXcXEiXMePyt9JRXUXr6qg4h6mha66aOadJq rYH+W2Y1HtDYSa/ELCo30dCjOw1fX/9oY5RGYwgVI8K8XAlr5p7MDHDvTz1Upckf3/u/ AsyQE1QnpZDmWsU+zaf7tO4MOfAhPxoyARbnMXignfSDFKAzuBF6i3k1NOBYFee8BZpG OW+8ikbKmZtwPh5Y96FViBfHs2KMOHFmiJt5ERFtdtEP/LUD9Sln09DWQEPwgjFbpdWu b1JAgiJH4FOAmxz4cRIXKFO68vfpw42o3wg7yBGRQl6rQB4hKSJA/mwhT73i7TrlH+wp 6NvA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:message-id:in-reply-to:subject :cc:to:from:date:delivered-to:list-id:list-subscribe :list-unsubscribe:list-help:list-post:precedence:mailing-list :arc-authentication-results; bh=O4WQIHzJCABpX66bp0kYm/q6o6J6W+S68WBAXqR2MbA=; b=AgeYcRzQ6VVGSCyKSrG4XKkL+Gk9JnXTad0uRWX9dZyp2aYt9/ioi6T/ww4/paS6SW AspfARJ0R/92ZN9s4fpc9cPHDHvjkm/ScaMqXCmG072SgAczf4aOpT8SRo/pTpwFua56 qOByfJP9kRRfzumV3c478uCydxVlzzX2uphxCrRU6+0TJ3+uvnq8LCIE8mN+5un643C/ YhEfZqPR+SGwYZp/m+MrPZ9ODZAgydozl4sIMYUcE31LmnD9rLswq7RO++jqlx2u5cO8 EoL5XRk9pCJcKd16DcYnexlROiX5kEbXhPmPEzgaKHLaZjPlKt3/tRRLMjsNv/8IBouE C/4g== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-12510-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12510-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-12510-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12510-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: X-IronPort-AV: E=Sophos;i="5.47,465,1515452400"; d="scan'208";a="258178898" Date: Tue, 13 Mar 2018 18:19:51 +0100 (CET) From: Julia Lawall X-X-Sender: jll@hadrien To: Matthew Wilcox cc: Julia Lawall , Kees Cook , Andrew Morton , Matthew Wilcox , Linux-MM , LKML , Kernel Hardening , cocci@systeme.lip6.fr, Himanshu Jha Subject: Re: [PATCH 2/2] mm: Add kvmalloc_ab_c and kvzalloc_struct In-Reply-To: <20180308230512.GD29073@bombadil.infradead.org> Message-ID: References: <20180214182618.14627-1-willy@infradead.org> <20180214182618.14627-3-willy@infradead.org> <20180308025812.GA9082@bombadil.infradead.org> <20180308230512.GD29073@bombadil.infradead.org> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592401933337716102?= X-GMAIL-MSGID: =?utf-8?q?1594843845882742485?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, 8 Mar 2018, Matthew Wilcox wrote: > On Thu, Mar 08, 2018 at 07:24:47AM +0100, Julia Lawall wrote: > > On Wed, 7 Mar 2018, Matthew Wilcox wrote: > > > On Wed, Mar 07, 2018 at 10:18:21PM +0100, Julia Lawall wrote: > > > > > Otherwise, yes, please. We could build a coccinelle rule for > > > > > additional replacements... > > > > > > > > A potential semantic patch and the changes it generates are attached > > > > below. Himanshu Jha helped with its development. Working on this > > > > uncovered one bug, where the allocated array is too large, because the > > > > size provided for it was a structure size, but actually only pointers to > > > > that structure were to be stored in it. > > > > > > This is cool! Thanks for doing the coccinelle patch! Diffstat: > > > > > > 50 files changed, 81 insertions(+), 124 deletions(-) > > > > > > I find that pretty compelling. I'll repost the kvmalloc_struct patch > > > imminently. > > > > Thanks. So it's OK to replace kmalloc and kzalloc, even though they > > didn't previously consider vmalloc and even though kmalloc doesn't zero? > > We'll also need to replace the corresponding places where those structs > are freed with kvfree(). Can coccinelle handle that too? Is the use of vmalloc a necessary part of the design? Or could there be a non vmalloc versions for call sites that are already ok with that? julia > > There are a few other cases that use GFP_NOFS and GFP_NOWAIT, but I didn't > > transform those because the comment says that the flags should be > > GFP_KERNEL based. Should those be transformed too? > > The problem with non-GFP_KERNEL allocations is that vmalloc may have to > allocate page tables, which is always done with an implicit GFP_KERNEL > allocation. There's an intent to get rid of GFP_NOFS, but that's not > been realised yet (and I'm not sure of our strategy to eliminate it ... > I'll send a separate email about that). I'm not sure why anything's > trying to allocate with GFP_NOWAIT; can you send a list of those places? >