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 7C09BC433EF for ; Thu, 17 Mar 2022 17:43:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236989AbiCQRpK (ORCPT ); Thu, 17 Mar 2022 13:45:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236265AbiCQRpJ (ORCPT ); Thu, 17 Mar 2022 13:45:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1985ABF73; Thu, 17 Mar 2022 10:43:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5A283615B5; Thu, 17 Mar 2022 17:43:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B384C340E9; Thu, 17 Mar 2022 17:43:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647539031; bh=z8Hyj2T1/hH5P475SCzLF1KeVKuoHUYntggCqpCnmNg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eGYoPFptuQC82BGVF0qrXJJArBJZM+T5qtJbO9MT9WQcYlu8hdMVT2hNSdlOdeIxU Xm3zUC4JXELpxExrVThcKXPe0NpnIrsYialPWuwhsKJhjL/1Ux6jViN3xTIylDT0d8 Q1cmIDX+iYsqP6EBetXF3M8TRSiH0xnrRVbiMVpz2wZfa2RWgxaD9w/+BsHk0o5nrs dGJgPzxicp5XHm2/gbtyF9gIdWEA05DmqDN5wZcchTgh1j/mEnG1/WS3vUozmyUIb5 4m65paVeHGs7zm3kD4WeR3iVWZfCEVh1Njg5Lpa8tvlNlfIQ7NwtrGqrLcrlYKfF5J R7Um6nNSSjChA== Date: Thu, 17 Mar 2022 10:43:44 -0700 From: Nathan Chancellor To: Sven Schnelle Cc: Ritesh Harjani , Steven Rostedt , linux-ext4@vger.kernel.org, Jan Kara , Theodore Ts'o , Harshad Shirwadkar , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org, hca@linux.ibm.com Subject: Re: [PATCHv3 02/10] ext4: Fix ext4_fc_stats trace point Message-ID: References: <20220317145008.73nm7hqtccyjy353@riteshh-domain> 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 Thu, Mar 17, 2022 at 05:11:42PM +0100, Sven Schnelle wrote: > Hi, > > Ritesh Harjani writes: > > > On 22/03/17 01:01PM, Sven Schnelle wrote: > >> Ritesh Harjani writes: > >> > >> [ 0.958403] Hardware name: IBM 3906 M04 704 (z/VM 7.1.0) > >> [ 0.958407] Workqueue: eval_map_wq eval_map_work_func > >> > >> [ 0.958446] Krnl PSW : 0704e00180000000 000000000090a9d6 (number+0x25e/0x3c0) > >> [ 0.958456] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 > >> [ 0.958461] Krnl GPRS: 0000000000000058 00000000010de0ac 0000000000000001 00000000fffffffc > >> [ 0.958467] 0000038000047b80 0affffff010de0ab 0000000000000000 0000000000000000 > >> [ 0.958481] 0000000000000020 0000038000000000 00000000010de0ad 00000000010de0ab > >> [ 0.958484] 0000000080312100 0000000000e68910 0000038000047b50 0000038000047ab8 > >> [ 0.958494] Krnl Code: 000000000090a9c6: f0c84112b001 srp 274(13,%r4),1(%r11),8 > >> [ 0.958494] 000000000090a9cc: 41202001 la %r2,1(%r2) > >> [ 0.958494] #000000000090a9d0: ecab0006c065 clgrj %r10,%r11,12,000000000090a9dc > >> [ 0.958494] >000000000090a9d6: d200b0004000 mvc 0(1,%r11),0(%r4) > >> [ 0.958494] 000000000090a9dc: 41b0b001 la %r11,1(%r11) > >> [ 0.958494] 000000000090a9e0: a74bffff > >> aghi %r4,-1 > >> [ 0.958494] 000000000090a9e4: a727fff6 brctg %r2,000000000090a9d0 > >> [ 0.958494] 000000000090a9e8: a73affff ahi %r3,-1 > >> [ 0.958575] Call Trace: > >> [ 0.958580] [<000000000090a9d6>] number+0x25e/0x3c0 > >> [ 0.958594] ([<0000000000289516>] update_event_printk+0xde/0x200) > >> [ 0.958602] [<0000000000910020>] vsnprintf+0x4b0/0x7c8 > >> [ 0.958606] [<00000000009103e8>] snprintf+0x40/0x50 > >> [ 0.958610] [<00000000002893d2>] eval_replace+0x62/0xc8 > >> [ 0.958614] [<000000000028e2fe>] trace_event_eval_update+0x206/0x248 > > > > This looks like you must have this patch from Steven as well [2]. > > Although I did test the patch and didn't see such a crash on my qemu box [3]. Indeed, commit b3bc8547d3be ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well") from the ftrace tree is required to reproduce this. The ftrace and ext4 changes alone are fine (my initial bisect landed on a merge and I did two more bisects to confirm that). > > [2]: https://lore.kernel.org/linux-ext4/20220310233234.4418186a@gandalf.local.home/ > > [3]: https://lore.kernel.org/linux-ext4/20220311051249.ltgqbjjothbrkbno@riteshh-domain/ > > > > @Steven, > > Sorry to bother. But does this crash strike anything obvious to you? > > Looking at the oops output again made me realizes that the snprintf > tries to write into pages that are mapped RO. Talking to Heiko he > mentioned that s390 maps rodata/text RO when setting up the initial > mapping while x86 has a RW mapping in the beginning and changes that > later to RO. I haven't verified that, but that might be a reason why it > works on x86. For what it's worth, this is reproducible on all of my x86 boxes during the initial boot on next-20220316 and newer. I am happy to test any patches or provide further information as necessary. Cheers, Nathan