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 919B0C433F5 for ; Mon, 22 Nov 2021 08:23:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238670AbhKVI0T (ORCPT ); Mon, 22 Nov 2021 03:26:19 -0500 Received: from out0.migadu.com ([94.23.1.103]:20443 "EHLO out0.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230487AbhKVI0T (ORCPT ); Mon, 22 Nov 2021 03:26:19 -0500 Subject: Re: [PATCH] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1637569389; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sM310Er7mKkSAbuzVmRMZZ3f2U9XAPXEmLcnEmNVRUo=; b=Ee83SsSc/A1AnNeAwqj6pLR+t8La07Zfi7WBhXGS1c2lnfiGxQv+PwSsr2ucgMOofIRKRZ 7kuye48BvgoXdwtnmNTCGZ1+PMdVJJyE1kQ4qk0Vn0gy/8bnpuFEy4jSQQqzyausL/cTiV 7kL4hOpQFSb23cYL9m1mTCNgDKxu2E8= To: Jinpu Wang , Leon Romanovsky Cc: haris.iqbal@ionos.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org References: <20211121142223.22887-1-guoqing.jiang@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Guoqing Jiang Message-ID: Date: Mon, 22 Nov 2021 16:23:03 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 11/22/21 4:20 PM, Jinpu Wang wrote: > On Mon, Nov 22, 2021 at 8:44 AM Leon Romanovsky wrote: >> 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? > Right, indeed. guoqing, mind to respin? I just see this calltrace, probably other paths are not triggered since the connection can't be established. Anyway, will send v2. Thanks, Guoqing