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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CB7B8C531FA for ; Fri, 24 Jul 2026 15:10:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tb5O8wjKcs1Pw/yvf0gMKaayemz7IuqUU9nVaaWlvg8=; b=DtlscumxZadmlz45yVams03tEq rTBx3d8ngbPmpIW5Iyuwm5eCRxGg99rBiq0pSjPJcbKzaS7S1ypJ3ycSP3nUtRt2PyeWWeru7qn30 OMJUVdGYrvkDxAzPdLzhamxK7CNIXBFAxwS2Ur36rhXheuJs+6Uj7pj3BnZRAbtV8TdDKIEgUrilp 5wRc6EU0FTTPTWt9+MFDSeDpW7uu2BEWEeIUKS1sN9OV+AbYkNBxjlfrBYwnWFoxGuHzAAUBD6YhK w30JsmAjauxYyxBnLqvC31DejIch+wXcwa1agQNxXrMowvLWecBhLIvxR0mNJrvQ6Bfz3O8zMaVJ6 C0DNWYww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wnHXU-0000000Geb8-1ksz; Fri, 24 Jul 2026 15:10:16 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wnHXS-0000000Gear-20SD for linux-arm-kernel@lists.infradead.org; Fri, 24 Jul 2026 15:10:14 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 282A24323D; Fri, 24 Jul 2026 15:10:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AADC81F000E9; Fri, 24 Jul 2026 15:10:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784905814; bh=tb5O8wjKcs1Pw/yvf0gMKaayemz7IuqUU9nVaaWlvg8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=clXeYOxQXDLXpoAFDrENkwTGS7dui0fvsU/h7Ajf1ew3+S1zHO/VInmDubBEe3KWJ JX6jw8hkeIkNGGu6MY3CNkRCy3HysYs8Nb1uimnA1D4lSbUVRwffoZHRkJC3MpQAuL Z2MKlVbWshUBo2CLTVtcgzh9vLEcvQCh1dCSo2VQvftbC9Fv41taVeNEu9puIqTQQT fx5k1OoQV4j+3oVp7dQXtTWzQb0HpQWJfKB/UC0e9LAAJYVebm2TTU0e49BOMnI8WG BNvgUvp4of6vGbUSykKTAFl/EXryoPxo8uD4ojxLNdMP6+36VCT5lSZ1apZFEeCgdU Dvo0Dg6q+d4IA== Date: Fri, 24 Jul 2026 16:09:53 +0100 From: "Lorenzo Stoakes (ARM)" To: Andrew Morton Cc: Suren Baghdasaryan , "Liam R. Howlett" , Vlastimil Babka , Shakeel Butt , David Hildenbrand , Mike Rapoport , Michal Hocko , Uladzislau Rezki , Toshi Kani , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Kiryl Shutsemau , Catalin Marinas , Will Deacon , Dev Jain , Ryan Roberts , David Carlier , linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Denis V. Lunev" , "Borah, Chaitanya Kumar" , stable@vger.kernel.org, syzbot+fd95a72470f5a44e464c@syzkaller.appspotmail.com Subject: Re: [PATCH mm-hotfixes v6 0/5] mm: fix UAF caused by race between ptdump and vmap pgtable freeing Message-ID: References: <20260723-series-vmap-race-fix-v6-0-8cc77dcc0018@kernel.org> <20260723162646.350cf3bf415a0855140d139b@linux-foundation.org> <20260723163233.54b38cfc682a25eb6edf7cc7@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260723163233.54b38cfc682a25eb6edf7cc7@linux-foundation.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 23, 2026 at 04:32:33PM -0700, Andrew Morton wrote: > On Thu, 23 Jul 2026 16:26:46 -0700 Andrew Morton wrote: > > > @@ -1250,7 +1251,11 @@ static int split_large_page(struct cpa_d > > > > if (!debug_pagealloc_enabled()) > > spin_unlock(&cpa_lock); > > + if (cpa->init_mm_read_locked) > > + mmap_read_unlock(&init_mm); > > ptdesc = pagetable_alloc(GFP_KERNEL, 0); > > + if (cpa->init_mm_read_locked) > > + mmap_read_lock(&init_mm); > > if (!debug_pagealloc_enabled()) > > spin_lock(&cpa_lock); > > if (!ptdesc) > > btw, this affects your later "x86/mm/pat: allocate split page tables as > kernel page tables". Which I resolved thusly: > > static int split_large_page(struct cpa_data *cpa, pte_t *kpte, > unsigned long address) > { > pte_t *pte; > > if (!debug_pagealloc_enabled()) > spin_unlock(&cpa_lock); > if (cpa->init_mm_read_locked) > mmap_read_unlock(&init_mm); > pte = pte_alloc_one_kernel(&init_mm); > if (cpa->init_mm_read_locked) > mmap_read_lock(&init_mm); > if (!debug_pagealloc_enabled()) > spin_lock(&cpa_lock); > if (!pte) > return -ENOMEM; > > if (__split_large_page(cpa, kpte, address, pte)) > pte_free_kernel(&init_mm, pte); > > return 0; > } > > Thanks that's correct! Cheers, Lorenzo