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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 814B5C433FE for ; Fri, 8 Oct 2021 08:44:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66DDD610D1 for ; Fri, 8 Oct 2021 08:44:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234956AbhJHIp7 (ORCPT ); Fri, 8 Oct 2021 04:45:59 -0400 Received: from esa.microchip.iphmx.com ([68.232.153.233]:62447 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229877AbhJHIp4 (ORCPT ); Fri, 8 Oct 2021 04:45:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1633682641; x=1665218641; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=6Dm9aMViI8ReP+IFTphshx0D0ke/ykpEn4jugDYx6Ts=; b=rzuf7LTIxIgU6cYtTcO5o6r9bSFnOjO08NVYXFz0aaEOPdArU10v3CwI T+w7oco2JN3NRKH6KVUhwFICgl/iNAPapJqyya0dzzXgvqeZvslgXU+f4 7yvTc9OUC4FMRaI2ogTyhxyie7OlCsCrRhmttRaKgIhOj5yj4+DtglIeH hRqrVSRtpkCTrikpI2J3yQ6WCt7FOnFCPaz/2UYiaE6ALLCioga+qRMoF FI9b/vAPjf1E+FZdN+ZwFwuFolunHSTzIWHi3kBdJVOkaA+MbeS9iMogR IJQHM2WL60McK4nKvSNLqZyA3Kt5W0ObV7qoMgA1rXbDaCdZjoi1CITb9 w==; IronPort-SDR: XUAliwqaByR0S4MfZETclano9WkUxU+5vweg8Qu+XMTZhfnS61T9vlMsLgOa3Yyt8G5XsAV8LN YqAIn0qABtQC3uEk1nwhi2EiU0zfpuID7MukO1NRCuZ5w9jauzegpDQDlsBeuIhXJ9PlInaCR5 PtT91LFqrOst+Lr8ThhjgDXXL8eMypg5GVCRRdyyEsZ02z0/lMEAOmy71CEsKefjmQBCOhvlFL kgoPinCAs4dXtMii+nglzfAuJ0X2JwrH11eI3Vquf+3UwwaLcxy4elWimWxXyfYZ1iZATR8hru nPXHvMTs1zYQW32vMvOd4Myj X-IronPort-AV: E=Sophos;i="5.85,357,1624345200"; d="scan'208";a="147263658" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa1.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 08 Oct 2021 01:44:00 -0700 Received: from chn-vm-ex04.mchp-main.com (10.10.85.152) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Fri, 8 Oct 2021 01:44:00 -0700 Received: from CHE-LT-I17769U.microchip.com (10.10.115.15) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server id 15.1.2176.14 via Frontend Transport; Fri, 8 Oct 2021 01:43:54 -0700 From: Arun Ramadoss To: , CC: George McCollister , Jakub Kicinski , "David S. Miller" , Vladimir Oltean , Florian Fainelli , Vivien Didelot , Andrew Lunn , , Woojung Huh Subject: [PATCH net] net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work Date: Fri, 8 Oct 2021 14:13:48 +0530 Message-ID: <20211008084348.7306-1-arun.ramadoss@microchip.com> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the ksz module is installed and removed using rmmod, kernel crashes with null pointer dereferrence error. During rmmod, ksz_switch_remove function tries to cancel the mib_read_workqueue using cancel_delayed_work_sync routine. At the end of mib_read_workqueue execution, it again reschedule the workqueue unconditionally. Due to which queue rescheduled after mib_interval, during this execution it tries to access dp->slave. But the slave is unregistered in the ksz_switch_remove function. Hence kernel crashes. To avoid this crash, before canceling the workqueue, resetted the mib_interval to 0. In the work queue execution, it schedules the workqueue next time only if the mib_interval is non zero. Fixes: 469b390e1ba3 ("net: dsa: microchip: use delayed_work instead of timer + work") Signed-off-by: Arun Ramadoss --- drivers/net/dsa/microchip/ksz_common.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c index 1542bfb8b5e5..ffc8e6fb300a 100644 --- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -94,7 +94,8 @@ static void ksz_mib_read_work(struct work_struct *work) mutex_unlock(&mib->cnt_mutex); } - schedule_delayed_work(&dev->mib_read, dev->mib_read_interval); + if (dev->mib_read_interval) + schedule_delayed_work(&dev->mib_read, dev->mib_read_interval); } void ksz_init_mib_timer(struct ksz_device *dev) @@ -449,8 +450,10 @@ EXPORT_SYMBOL(ksz_switch_register); void ksz_switch_remove(struct ksz_device *dev) { /* timer started */ - if (dev->mib_read_interval) + if (dev->mib_read_interval) { + dev->mib_read_interval = 0; cancel_delayed_work_sync(&dev->mib_read); + } dev->dev_ops->exit(dev); dsa_unregister_switch(dev->ds); -- 2.33.0