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 40994C433F5 for ; Tue, 25 Jan 2022 17:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356909AbiAYRe6 (ORCPT ); Tue, 25 Jan 2022 12:34:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:60272 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1588385AbiAYRdC (ORCPT ); Tue, 25 Jan 2022 12:33:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643131981; 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=hHrbMaICyVWZJZVuCs/Sc0unbjuRdIuWQiuze8whQJY=; b=Lfj+hvtBq2fAum6Ch/KcNUdzyRv+WO15P0rWIOW0bXjxcuzVhuG6JJYgld+z0yBGVJKkMZ DMwv0J6wQ635cLctfVece7s0tm5DohrLzE05lPr20TooKc1mTTyNBW0ET1hV9OB7ms3rMk 2Nd2HU9mSjyBcx5W4mcRMmCvdJCmgC0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-634-uXO9vnS6NjyFGN3gckN4iA-1; Tue, 25 Jan 2022 12:32:58 -0500 X-MC-Unique: uXO9vnS6NjyFGN3gckN4iA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 00FD81006AA6; Tue, 25 Jan 2022 17:32:57 +0000 (UTC) Received: from [10.22.34.217] (unknown [10.22.34.217]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8097E22DEB; Tue, 25 Jan 2022 17:32:55 +0000 (UTC) Message-ID: Date: Tue, 25 Jan 2022 12:32:54 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH] scsi: bnx2fc: make bnx2fc_recv_frame mp safe Content-Language: en-US From: John Meneghini To: skashyap@marvell.com, njavali@marvell.com, mlombard@redhat.com Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, GR-QLogic-Storage-Upstream@marvell.com, "Martin K. Petersen" References: <20220124145110.442335-1-jmeneghi@redhat.com> Organization: RHEL Core Storge Team In-Reply-To: <20220124145110.442335-1-jmeneghi@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Can I please get a review and approval for this patch? I'd like this to get into v5.17-rc2 Thanks, /John On 1/24/22 09:51, John Meneghini wrote: > Running tests with a debug kernel shows that bnx2fc_recv_frame is > modifying the per_cpu lport stats counters in a non-mpsafe way. > Just boot a debug kernel and run the bnx2fc driver with the hardware > enabled. > > [ 1391.699147] BUG: using smp_processor_id() in preemptible [00000000] code: bnx2fc_ > [ 1391.699160] caller is bnx2fc_recv_frame+0xbf9/0x1760 [bnx2fc] > [ 1391.699174] CPU: 2 PID: 4355 Comm: bnx2fc_l2_threa Kdump: loaded Tainted: G B > [ 1391.699180] Hardware name: HP ProLiant DL120 G7, BIOS J01 07/01/2013 > [ 1391.699183] Call Trace: > [ 1391.699188] dump_stack_lvl+0x57/0x7d > [ 1391.699198] check_preemption_disabled+0xc8/0xd0 > [ 1391.699205] bnx2fc_recv_frame+0xbf9/0x1760 [bnx2fc] > [ 1391.699215] ? do_raw_spin_trylock+0xb5/0x180 > [ 1391.699221] ? bnx2fc_npiv_create_vports.isra.0+0x4e0/0x4e0 [bnx2fc] > [ 1391.699229] ? bnx2fc_l2_rcv_thread+0xb7/0x3a0 [bnx2fc] > [ 1391.699240] bnx2fc_l2_rcv_thread+0x1af/0x3a0 [bnx2fc] > [ 1391.699250] ? bnx2fc_ulp_init+0xc0/0xc0 [bnx2fc] > [ 1391.699258] kthread+0x364/0x420 > [ 1391.699263] ? _raw_spin_unlock_irq+0x24/0x50 > [ 1391.699268] ? set_kthread_struct+0x100/0x100 > [ 1391.699273] ret_from_fork+0x22/0x30 > > To fix the problem: restore the old get_cpu/put_cpu code with some > modifications to reduce the size of the critical section. > > Fixes: d576a5e80cd0 ("bnx2fc: Improve stats update mechanism") > Tested-by: Guangwu Zhang > Signed-off-by: John Meneghini > --- > drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 21 +++++++++++++-------- > 1 file changed, 13 insertions(+), 8 deletions(-) > > diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c > index 71fa62bd3083..e41a94dc2d1f 100644 > --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c > +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c > @@ -508,7 +508,8 @@ static int bnx2fc_l2_rcv_thread(void *arg) > > static void bnx2fc_recv_frame(struct sk_buff *skb) > { > - u32 fr_len; > + u64 crc_err; > + u32 fr_len, fr_crc; > struct fc_lport *lport; > struct fcoe_rcv_info *fr; > struct fc_stats *stats; > @@ -542,6 +543,11 @@ static void bnx2fc_recv_frame(struct sk_buff *skb) > skb_pull(skb, sizeof(struct fcoe_hdr)); > fr_len = skb->len - sizeof(struct fcoe_crc_eof); > > + stats = per_cpu_ptr(lport->stats, get_cpu()); > + stats->RxFrames++; > + stats->RxWords += fr_len / FCOE_WORD_TO_BYTE; > + put_cpu(); > + > fp = (struct fc_frame *)skb; > fc_frame_init(fp); > fr_dev(fp) = lport; > @@ -624,16 +630,15 @@ static void bnx2fc_recv_frame(struct sk_buff *skb) > return; > } > > - stats = per_cpu_ptr(lport->stats, smp_processor_id()); > - stats->RxFrames++; > - stats->RxWords += fr_len / FCOE_WORD_TO_BYTE; > + fr_crc = le32_to_cpu(fr_crc(fp)); > > - if (le32_to_cpu(fr_crc(fp)) != > - ~crc32(~0, skb->data, fr_len)) { > - if (stats->InvalidCRCCount < 5) > + if (unlikely(fr_crc != ~crc32(~0, skb->data, fr_len))) { > + stats = per_cpu_ptr(lport->stats, get_cpu()); > + crc_err = (stats->InvalidCRCCount++); > + put_cpu(); > + if (crc_err < 5) > printk(KERN_WARNING PFX "dropping frame with " > "CRC error\n"); > - stats->InvalidCRCCount++; > kfree_skb(skb); > return; > }