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 0CCC2CD13D2 for ; Mon, 18 Sep 2023 18:42:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229778AbjIRSmJ (ORCPT ); Mon, 18 Sep 2023 14:42:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229770AbjIRSmI (ORCPT ); Mon, 18 Sep 2023 14:42:08 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05486FC; Mon, 18 Sep 2023 11:42:02 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A2D7C433C9; Mon, 18 Sep 2023 18:42:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695062521; bh=ecOplp0N39eFmx3h8Tyj1e5FA83CwJjtLZ8S7+4v1Gk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JVBJqfiJBIpr+eauKB80fDRk/oQSO0zP7KLthqdCGos6whA/y0ay6T1V1QTYKjC9c c3fgHTW+BJlMlFlc0AK5tU6VrUpGcuEgVvhIVCQH/fL3NefXuhXtA9D+xa4FKqDCwg d2kvHewr943K2fzqPUtAbywwR+tg4hOIaPbc8HlA6i6ZgocgNRoVGvNTbO6iqq1K2v h5yRG60xMrsiHD4DWCpYg9T8HMjerGiKbGQ0bG9n8/51yH5HLQZt5K1/fFYdoS4vRb QnUNA+gnDkLOt45zxIwGu4gNvf4zLFxS8j15swM5YD1gXBIwSd2gWGcMMyGG8eLRs/ Lg9rin4Gh2N5w== Date: Mon, 18 Sep 2023 11:42:00 -0700 From: "Darrick J. Wong" To: Baokun Li Cc: Peter Zijlstra , Yi Zhang , Ming Lei , mark.rutland@arm.com, Christian Brauner , linux-fsdevel@vger.kernel.org, Alexander Viro , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Changhui Zhong , yangerkun , "zhangyi (F)" , Kees Cook , chengzhihao Subject: Re: [czhong@redhat.com: [bug report] WARNING: CPU: 121 PID: 93233 at fs/dcache.c:365 __dentry_kill+0x214/0x278] Message-ID: <20230918184200.GA347993@frogsfrogsfrogs> References: <20230823-kuppe-lassen-bc81a20dd831@brauner> <89d049ed-6bbf-bba7-80d4-06c060e65e5b@huawei.com> <20230917091031.GA1543@noisy.programming.kicks-ass.net> <20230917092616.GA8409@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Sep 18, 2023 at 09:52:28AM +0800, Baokun Li wrote: > On 2023/9/17 17:26, Peter Zijlstra wrote: > > On Sun, Sep 17, 2023 at 11:10:32AM +0200, Peter Zijlstra wrote: > > > On Sat, Sep 16, 2023 at 02:55:47PM +0800, Baokun Li wrote: > > > > On 2023/9/13 16:59, Yi Zhang wrote: > > > > > The issue still can be reproduced on the latest linux tree[2]. > > > > > To reproduce I need to run about 1000 times blktests block/001, and > > > > > bisect shows it was introduced with commit[1], as it was not 100% > > > > > reproduced, not sure if it's the culprit? > > > > > > > > > > > > > > > [1] 9257959a6e5b locking/atomic: scripts: restructure fallback ifdeffery > > > > Hello, everyone！ > > > > > > > > We have confirmed that the merge-in of this patch caused hlist_bl_lock > > > > (aka, bit_spin_lock) to fail, which in turn triggered the issue above. > > > > [root@localhost ~]# insmod mymod.ko > > > > [   37.994787][  T621] >>> a = 725, b = 724 > > > > [   37.995313][  T621] ------------[ cut here ]------------ > > > > [   37.995951][  T621] kernel BUG at fs/mymod/mymod.c:42! > > > > [r[  oo 3t7@.l996o4c61al]h[o s T6t21] ~ ]#Int ernal error: Oops - BUG: > > > > 00000000f2000800 [#1] SMP > > > > [   37.997420][  T621] Modules linked in: mymod(E) > > > > [   37.997891][  T621] CPU: 9 PID: 621 Comm: bl_lock_thread2 Tainted: > > > > G            E      6.4.0-rc2-00034-g9257959a6e5b-dirty #117 > > > > [   37.999038][  T621] Hardware name: linux,dummy-virt (DT) > > > > [   37.999571][  T621] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS > > > > BTYPE=--) > > > > [   38.000344][  T621] pc : increase_ab+0xcc/0xe70 [mymod] > > > > [   38.000882][  T621] lr : increase_ab+0xcc/0xe70 [mymod] > > > > [   38.001416][  T621] sp : ffff800008b4be40 > > > > [   38.001822][  T621] x29: ffff800008b4be40 x28: 0000000000000000 x27: > > > > 0000000000000000 > > > > [   38.002605][  T621] x26: 0000000000000000 x25: 0000000000000000 x24: > > > > 0000000000000000 > > > > [   38.003385][  T621] x23: ffffd9930c698190 x22: ffff800008a0ba38 x21: > > > > 0000000000000001 > > > > [   38.004174][  T621] x20: ffffffffffffefff x19: ffffd9930c69a580 x18: > > > > 0000000000000000 > > > > [   38.004955][  T621] x17: 0000000000000000 x16: ffffd9933011bd38 x15: > > > > ffffffffffffffff > > > > [   38.005754][  T621] x14: 0000000000000000 x13: 205d313236542020 x12: > > > > ffffd99332175b80 > > > > [   38.006538][  T621] x11: 0000000000000003 x10: 0000000000000001 x9 : > > > > ffffd9933022a9d8 > > > > [   38.007325][  T621] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : > > > > ffffd993320b5b40 > > > > [   38.008124][  T621] x5 : ffff0001f7d1c708 x4 : 0000000000000000 x3 : > > > > 0000000000000000 > > > > [   38.008912][  T621] x2 : 0000000000000000 x1 : 0000000000000000 x0 : > > > > 0000000000000015 > > > > [   38.009709][  T621] Call trace: > > > > [   38.010035][  T621]  increase_ab+0xcc/0xe70 [mymod] > > > > [   38.010539][  T621]  kthread+0xdc/0xf0 > > > > [   38.010927][  T621]  ret_from_fork+0x10/0x20 > > > > [   38.011370][  T621] Code: 17ffffe0 90000020 91044000 9400000d (d4210000) > > > > [   38.012067][  T621] ---[ end trace 0000000000000000 ]--- > > > Is this arm64 or something? You seem to have forgotten to mention what > > > platform you're using. > > Is that an LSE or LLSC arm64 ? > > I'm not sure how to distinguish if it's LSE or LLSC, here's some info on the > cpu: > > $ cat /sys/devices/system/cpu/cpu0/regs/identification/midr_el1 > 0x00000000481fd010 > > $ lscpu > Architecture:        aarch64 > Byte Order:          Little Endian > CPU(s):              96 > On-line CPU(s) list: 0-95 > Thread(s) per core:  1 > Core(s) per socket:  48 > Socket(s):           2 > NUMA node(s):        4 > Vendor ID:           HiSilicon > BIOS Vendor ID:      HiSilicon > Model:               0 > Model name:          Kunpeng-920 > BIOS Model name:     Kunpeng 920-4826 > Stepping:            0x1 > BogoMIPS:            200.00 > L1d cache:           64K > L1i cache:           64K > L2 cache:            512K > L3 cache:            49152K > NUMA node0 CPU(s):   0-23 > NUMA node1 CPU(s):   24-47 > NUMA node2 CPU(s):   48-71 > NUMA node3 CPU(s):   72-95 > Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp > asimdhp cpuid asimdrdm jscvt fcma dcpop asimddp asimdfhm > > > Anyway, it seems that ARM64 shouldn't be using the fallback as it does > > everything itself. > > > > Mark, can you have a look please? At first glance the > > atomic64_fetch_or_acquire() that's being used by generic bitops/lock.h > > seems in order.. > > > We also suspect some implicit mechanism change in > raw_atomic64_fetch_or_acquire. You can reproduce the problem with the > above mod that can reproduce the problem to make it easier to locate. > I can help reproduce it and grab some information if you can't reproduce > it on your end. FWIW this looks a lot like the crash I reported last week: https://lore.kernel.org/linux-fsdevel/ZQep0OR0uMmR%2Fwg3@dread.disaster.area/T/#t Also arm64, but virtualized. I /think/ the host is some Ampere box, though I have no idea what kind since it's just some Oracle Cloud A1 instance. The internet claims "Ampere Altra" processors[1]. # lscpu Architecture: aarch64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 2 On-line CPU(s) list: 0,1 Vendor ID: ARM Model name: Neoverse-N1 Model: 1 Thread(s) per core: 1 Core(s) per socket: 2 Socket(s): 1 Stepping: r3p1 BogoMIPS: 50.00 Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp ssbs NUMA: NUMA node(s): 1 NUMA node0 CPU(s): 0,1 Vulnerabilities: Gather data sampling: Not affected Itlb multihit: Not affected L1tf: Not affected Mds: Not affected Meltdown: Not affected Mmio stale data: Not affected Retbleed: Not affected Spec rstack overflow: Not affected Spec store bypass: Vulnerable Spectre v1: Mitigation; __user pointer sanitization Spectre v2: Mitigation; CSV2, but not BHB Srbds: Not affected Tsx async abort: Not affected [1] https://www.oracle.com/cloud/compute/arm/ --D > -- > With Best Regards, > Baokun Li > .