From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zeniv.linux.org.uk ([195.92.253.2]:33428 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752084AbcFCVqd (ORCPT ); Fri, 3 Jun 2016 17:46:33 -0400 Date: Fri, 3 Jun 2016 22:46:31 +0100 From: Al Viro To: Oleg Drokin Cc: " Mailing List" , "" , Linus Torvalds Subject: Re: Dcache oops Message-ID: <20160603214630.GU14480@ZenIV.linux.org.uk> References: <20160603033750.GL14480@ZenIV.linux.org.uk> <0C971585-6BFC-4665-832B-9B262F733BFC@linuxhacker.ru> <20160603042648.GN14480@ZenIV.linux.org.uk> <74306F63-DBDF-4DED-85D2-5C3FB21B8A1E@linuxhacker.ru> <20160603182203.GR14480@ZenIV.linux.org.uk> <4285E00F-7228-485C-AD32-97552ED746F2@linuxhacker.ru> <20160603200759.GS14480@ZenIV.linux.org.uk> <691D0636-F1E8-4C94-B2BB-9B66618699C9@linuxhacker.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <691D0636-F1E8-4C94-B2BB-9B66618699C9@linuxhacker.ru> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Jun 03, 2016 at 05:17:06PM -0400, Oleg Drokin wrote: > > Can the same thing be reproduced (with NFS fix) on v4.6, ede4090, 7f427d3, > > 4e8440b? > > Well, that was faster than I expected. 4e8440b triggers right away, so I guess > there's no point in trying the later ones? > BTW, just to confirm you are noticing - this is a DEBUG_PAGEALLOC build, > so all freed memory is unmapped which is likely causing this oops - as a sign > of use after free. > [ 54.990119] BUG: unable to handle kernel paging request at ffff8800d2b7f000 Again a page-aligned nd->last.name and even smaller nd->last.len. It smells like a page that used to contain a symlink body, but got freed under us.