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[70.31.27.79]) by smtp.gmail.com with ESMTPSA id bn1-20020a05620a2ac100b006ce3cffa2c8sm521364qkb.43.2022.10.24.12.43.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Oct 2022 12:43:01 -0700 (PDT) Date: Mon, 24 Oct 2022 15:42:59 -0400 From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Axel Rasmussen , Andrew Morton , Andrea Arcangeli , Nadav Amit Subject: Re: [PATCH 1/2] mm/uffd: Fix vma check on userfault for wp Message-ID: References: <20221024193336.1233616-1-peterx@redhat.com> <20221024193336.1233616-2-peterx@redhat.com> MIME-Version: 1.0 In-Reply-To: <20221024193336.1233616-2-peterx@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666640584; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=aS4yi1vMu6K7Mzb0dwDEe+zwP7hRRYhJ4HxVAVJl5ro=; b=oY6Sw4Qul6s6qVHcFjQUTAkMPv/jJKP58baPKIOaVD8Y4IAmS/0maEcTf6DrZjEDHuvDMl NvRiqk2GzE5nIjL21d+KW4Kv81kCGf1ppO9hClW318DbogFKMnGTxPpqV4lgch+dSf8smp gtADO6ChLjIeG6W1lIsrtDK0LHZw2Ng= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=C0+q+S1k; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf13.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666640584; a=rsa-sha256; cv=none; b=T7atf0n8le/zMXd6dTVeKj3tUTz4Bly1mV1N/h0W5uFaGLOamlZX0kNPINImYRNKYYYCPB Vqpwe0+Fj+D3lgdsYlgH2SiPuUe2OCsUDOkAxYTT922pTgjbOFv01b0OnST7IlvQ3XE05K sUWmStnuUWGNWZAELDEdVmfmnhT87Sw= X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 5EAB520014 X-Rspam-User: Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=C0+q+S1k; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf13.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com X-Stat-Signature: 8incqno58qrmuxwrx53j8z97jus4nmr6 X-HE-Tag: 1666640584-791384 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Oct 24, 2022 at 03:33:35PM -0400, Peter Xu wrote: > We used to have a report that pte-marker code can be reached even when > uffd-wp is not compiled in for file memories, here: > > https://lore.kernel.org/all/YzeR+R6b4bwBlBHh@x1n/T/#u > > I just got time to revisit this and found that the root cause is we simply > messed up with the vma check, so that for !PTE_MARKER_UFFD_WP system, we > will allow UFFDIO_REGISTER of MINOR & WP upon shmem as the check was wrong: > > if (vm_flags & VM_UFFD_MINOR) > return is_vm_hugetlb_page(vma) || vma_is_shmem(vma); > > Where we'll allow anything to pass on shmem as long as minor mode is > requested. > > Axel did it right when introducing minor mode but I messed it up in > b1f9e876862d when moving code around. Fix it. > > Cc: Axel Rasmussen > Fixes: b1f9e876862d ("mm/uffd: enable write protection for shmem & hugetlbfs") Should also have had: Cc: stable@vger.kernel.org > Signed-off-by: Peter Xu -- Peter Xu