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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF2BEC2BD09 for ; Thu, 5 Dec 2019 16:34:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A69BB20801 for ; Thu, 5 Dec 2019 16:34:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XUtVhPuj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729836AbfLEQeE (ORCPT ); Thu, 5 Dec 2019 11:34:04 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:26185 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729022AbfLEQeE (ORCPT ); Thu, 5 Dec 2019 11:34:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575563643; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qxYFzUuTTdheWGBhhn3zwDRBiNCvQHjX+pYVvWctuZk=; b=XUtVhPujoCWCgmS4s6sLmeFgfaWvNS6S3661vl509+NEoo/f/trdn3Bn9EQQLFNfpW//ER rR6F+uBWvnQZAqtEOc75JdoQzFdyML8VYAbRHX1Bch42m6Jncg2Utga6O4yEZD91d7+mQW UJ1LU6pxFqgwWXZOMv0SHH2iMEwaKVM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-94-PYFfFydZOzOTHH3KkbAciA-1; Thu, 05 Dec 2019 11:34:00 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D5B85183B736; Thu, 5 Dec 2019 16:33:58 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-250.rdu2.redhat.com [10.10.120.250]) by smtp.corp.redhat.com (Postfix) with ESMTP id 809039F41; Thu, 5 Dec 2019 16:33:57 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20191205074539.GB3237@sol.localdomain> References: <20191205074539.GB3237@sol.localdomain> <000000000000a6324b0598b2eb59@google.com> <000000000000d6c9870598bdf090@google.com> To: Eric Biggers Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, syzbot Subject: Re: KASAN: slab-out-of-bounds Write in pipe_write MIME-Version: 1.0 Content-ID: <29473.1575563636.1@warthog.procyon.org.uk> Date: Thu, 05 Dec 2019 16:33:56 +0000 Message-ID: <29474.1575563636@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: PYFfFydZOzOTHH3KkbAciA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Eric Biggers wrote: > It looks like the 'mask' variable in pipe_write() is not being updated af= ter > the pipe mutex was dropped in pipe_wait(), to take into account the pipe > size possibly having been changed in the mean time. There's that, but not only that. Weirdness ensues if the ring size is 1 - this may have to do with the mask then being 0. David