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 3DAFBC433F5 for ; Sun, 28 Nov 2021 18:18:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347745AbhK1SVX (ORCPT ); Sun, 28 Nov 2021 13:21:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229770AbhK1STX (ORCPT ); Sun, 28 Nov 2021 13:19:23 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E50F6C061746 for ; Sun, 28 Nov 2021 10:16:06 -0800 (PST) Received: from mail.kernel.org (unknown [198.145.29.99]) (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 7AA7F610A1 for ; Sun, 28 Nov 2021 18:16:06 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 2C47060041; Sun, 28 Nov 2021 18:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638123365; bh=TNM7yu4eF4CklM3UuSYlo560O9ABw9r1m/qj+lObvoQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pMQyai7gZ9ybdRMp/TgTwAdAVvVVqoTAJgQ8z7heBCNTkmk2CJKlflq6s+B2WubJ/ JEQ7o0HOQXK/IiytkCVSD7Y4HMsronpQE4zkEpRdOINxrPzu8wEqg/rocWNsys1Zih Y21ZFBTwjUdXXCUH7TKgsVVQkY7o4L6ZuPhFK1bakQcs/81ezqqOP1zHx4lC90uCnF mm5DEzJ78IotZnZPdfQDJh3ma4QIxZytmm8Rx6+EVuPb7Fbipu/R2ilQyCJ64J82W8 Vyw+04sqrc55ckvyIOyNZsN+CcUBJY1C2MiXQxvFRd6IjNv81ZlseMDqCooockgk8x OZQIz7whJC/Wg== Date: Sun, 28 Nov 2021 20:16:01 +0200 From: Leon Romanovsky To: Guoqing Jiang Cc: jinpu.wang@ionos.com, haris.iqbal@ionos.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org Subject: Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Message-ID: References: <20211128133501.38710-1-guoqing.jiang@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211128133501.38710-1-guoqing.jiang@linux.dev> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Sun, Nov 28, 2021 at 09:35:01PM +0800, Guoqing Jiang wrote: > With preemption enabled (CONFIG_DEBUG_PREEMPT=y), the following appeared > when rnbd client tries to map remote block device. > > [ 2123.221071] BUG: using smp_processor_id() in preemptible [00000000] code: bash/1733 > [ 2123.221175] caller is debug_smp_processor_id+0x17/0x20 > [ 2123.221214] CPU: 0 PID: 1733 Comm: bash Not tainted 5.16.0-rc1 #5 > [ 2123.221218] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014 > [ 2123.221229] Call Trace: > [ 2123.221231] > [ 2123.221235] dump_stack_lvl+0x5d/0x78 > [ 2123.221252] dump_stack+0x10/0x12 > [ 2123.221257] check_preemption_disabled+0xe4/0xf0 > [ 2123.221266] debug_smp_processor_id+0x17/0x20 > [ 2123.221271] rtrs_clt_update_all_stats+0x3b/0x70 [rtrs_client] > [ 2123.221285] rtrs_clt_read_req+0xc3/0x380 [rtrs_client] > [ 2123.221298] ? rtrs_clt_init_req+0xe3/0x120 [rtrs_client] > [ 2123.221321] rtrs_clt_request+0x1a7/0x320 [rtrs_client] > [ 2123.221340] ? 0xffffffffc0ab1000 > [ 2123.221357] send_usr_msg+0xbf/0x160 [rnbd_client] > [ 2123.221370] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client] > [ 2123.221377] ? send_usr_msg+0x160/0x160 [rnbd_client] > [ 2123.221386] ? sg_alloc_table+0x27/0xb0 > [ 2123.221395] ? sg_zero_buffer+0xd0/0xd0 > [ 2123.221407] send_msg_sess_info+0xe9/0x180 [rnbd_client] > [ 2123.221413] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client] > [ 2123.221429] ? blk_mq_alloc_tag_set+0x2ef/0x370 > [ 2123.221447] rnbd_clt_map_device+0xba8/0xcd0 [rnbd_client] > [ 2123.221462] ? send_msg_open+0x200/0x200 [rnbd_client] > [ 2123.221479] rnbd_clt_map_device_store+0x3e5/0x620 [rnbd_client > > To supress the calltrace, let's call get_cpu_ptr/put_cpu_ptr pair in > rtrs_clt_update_rdma_stats to disable preemption when accessing per-cpu > variable. > > While at it, let's make the similar change in rtrs_clt_update_wc_stats. > And for rtrs_clt_inc_failover_cnt, though it was only called inside rcu > section, but it still can be preempted in case CONFIG_PREEMPT_RCU is > enabled, so change it to {get,put}_cpu_ptr pair either. > > Signed-off-by: Guoqing Jiang > --- > V2: also make the change in rtrs_clt_update_wc_stats and rtrs_clt_inc_failover_cnt > > drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > Thanks, Reviewed-by: Leon Romanovsky