From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D78F9C3DA78 for ; Tue, 17 Jan 2023 14:27:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232403AbjAQO1m (ORCPT ); Tue, 17 Jan 2023 09:27:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232474AbjAQO1G (ORCPT ); Tue, 17 Jan 2023 09:27:06 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64ECE2E0C2 for ; Tue, 17 Jan 2023 06:25:46 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 01F236883A; Tue, 17 Jan 2023 14:25:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1673965545; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=4qP0tqKbz89TqGC5y3LuOjWIwHkSRgjN6U77F+eqn9w=; b=Ke0+ixAxoITmtnbFSR9yQKvbE5qsqN0+thDtMoXNBuAZOOYw/jd2PVuLOGQQE7fmzHR7Un 9fZfqOZAJkq4JlLb2k4WM/j0lghlgFLqCny6lFkTbeJqtG7BG0MZK82AxYTOKXiQYtVbql 8EQv4oZhBf8wTBGiorzjnNRmetCWLrA= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id C3F3813357; Tue, 17 Jan 2023 14:25:44 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id vGCcLuivxmM0KAAAMHmgww (envelope-from ); Tue, 17 Jan 2023 14:25:44 +0000 Date: Tue, 17 Jan 2023 15:25:44 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, michel@lespinasse.org, jglisse@google.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH 09/41] mm: rcu safe VMA freeing Message-ID: References: <20230109205336.3665937-1-surenb@google.com> <20230109205336.3665937-10-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230109205336.3665937-10-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 09-01-23 12:53:04, Suren Baghdasaryan wrote: [...] > void vm_area_free(struct vm_area_struct *vma) > { > free_anon_vma_name(vma); > +#ifdef CONFIG_PER_VMA_LOCK > + call_rcu(&vma->vm_rcu, __vm_area_free); > +#else > kmem_cache_free(vm_area_cachep, vma); > +#endif Is it safe to have vma with already freed vma_name? I suspect this is safe because of mmap_lock but is there any reason to split the freeing process and have this potential UAF lurking? > } > > static void account_kernel_stack(struct task_struct *tsk, int account) > -- > 2.39.0 -- Michal Hocko SUSE Labs