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 73E7CC433F5 for ; Mon, 22 Nov 2021 07:44:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230142AbhKVHr3 (ORCPT ); Mon, 22 Nov 2021 02:47:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:53086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231360AbhKVHr2 (ORCPT ); Mon, 22 Nov 2021 02:47:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id AFC1B60F24; Mon, 22 Nov 2021 07:44:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637567062; bh=NnFCyGLBe9eZmqScFNZcEfdIpXXxcZlYJKlLn6gkZ7o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BfhwAaDKTcyr4WjFv9DnLpmnLdT1jfFw01sOKNCRoG/AN9yL+tMjKT+MlJzyqiELi Zczw9Orh17SBxILOBuQv+i/lp4xbBRgmqWahTU2vkW3w+QUmMhDtKXbQD6oh8ekz8y cTj/1slBjYMcVRSD0hL5lO7iDdwx2VK9+oxtEfwbobLQ2RfJp2t1jmMmUI4NsB+zgk 7TRNN2X8qVdRGxMz9PqfEQpJ/h+FrFtuYD+bKnGN9i6IyIbX32YaemSyXJiclpY/It DVAsQ69PUuXz7X2vMYE7VK1uvwNOqGM8H8Hvpw2dYV0WpT1/cUzZRSV4T5ioXVE4Fh gZsMHB9anmsDw== Date: Mon, 22 Nov 2021 09:44:18 +0200 From: Leon Romanovsky To: Guoqing Jiang Cc: haris.iqbal@ionos.com, jinpu.wang@ionos.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org Subject: Re: [PATCH] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Message-ID: References: <20211121142223.22887-1-guoqing.jiang@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211121142223.22887-1-guoqing.jiang@linux.dev> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Sun, Nov 21, 2021 at 10:22:23PM +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. > > Signed-off-by: Guoqing Jiang > --- > drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c > index f7e459fe68be..6ff72f2b1a3a 100644 > --- a/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c > +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c > @@ -169,9 +169,10 @@ static inline void rtrs_clt_update_rdma_stats(struct rtrs_clt_stats *stats, > { > struct rtrs_clt_stats_pcpu *s; > > - s = this_cpu_ptr(stats->pcpu_stats); > + s = get_cpu_ptr(stats->pcpu_stats); > s->rdma.dir[d].cnt++; > s->rdma.dir[d].size_total += size; > + put_cpu_ptr(stats->pcpu_stats); I see that this_cpu_ptr() is used in many other places in rtrs-clt-stats.c, why do we need to change only one place? Thanks > } > > void rtrs_clt_update_all_stats(struct rtrs_clt_io_req *req, int dir) > -- > 2.31.1 >