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 CED97C07E9D for ; Tue, 27 Sep 2022 18:06:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233065AbiI0SGg (ORCPT ); Tue, 27 Sep 2022 14:06:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232462AbiI0SGf (ORCPT ); Tue, 27 Sep 2022 14:06:35 -0400 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 371D6DB972 for ; Tue, 27 Sep 2022 11:06:34 -0700 (PDT) Received: from cwcc.thunk.org (pool-173-48-120-46.bstnma.fios.verizon.net [173.48.120.46]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 28RI6Ms4023728 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 27 Sep 2022 14:06:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1664301983; bh=yhvaj0nUCk4OWFKWOKG5BcM/LVVS+o0Dw7Fp/Y7/LyY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=HVUgh33KCBG1I7Ld+5xfGZ1fv6S8SO1Kcw3XG1IbLkq6QeshsawrkzXYekp2TtyQs dGxLqWnAcp+GtkrYCyqZSFY5URVUaG9ObcohjKgOJOC2KlGThWEaW/ewftC0nNT1h4 OlXeIoZYRwh826p3qpXTgcZAZhGqpC89NjpMgnUQNDI/3iyhE7XoiOMBB1DO5Jvw4Y eAGxUHHHadgklUzow5Yny+huq8rE6P6R3lvusEtH3qHD62ZbTl/0S/R9tt68GAMWol OCfEf43cj+5OwCVHBdYekcBbQtbVNdG2zidSySC/33NbYWZeHtqoplkvZdK3/JN2nS MZcv94Fxy/oBQ== Received: by cwcc.thunk.org (Postfix, from userid 15806) id 14B5D15C5266; Tue, 27 Sep 2022 14:06:22 -0400 (EDT) Date: Tue, 27 Sep 2022 14:06:22 -0400 From: "Theodore Ts'o" To: bugzilla-daemon@kernel.org Cc: linux-ext4@vger.kernel.org Subject: Re: [Bug 216529] [fstests generic/048] BUG: Kernel NULL pointer dereference at 0x00000069, filemap_release_folio+0x88/0xb0 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Sep 27, 2022 at 12:47:02AM +0000, bugzilla-daemon@kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=216529 > > Yes, it's reproducible for me, I just reproduced it again on another ppc64le > (P8) machine [1]. But it's not easy to reproduce by running generic/048 (maybe > there's a better way to reproduce it). Can you give a rough percentage of how often it reproduces? e.g., does it reproduces 10% of the time? 50% of the time? 2-3 times after 100 tries, so 2-3%? etc. If it reproduces but rarely, it'll be a lot harder to try to bisect. Something perhaps to try is to enable KASAN, since both stack traces seem to involve a null pointer derference while trying to free buffers. Maybe that will give us some hints towards the cause.... Thanks, - Ted