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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35155C433DB for ; Thu, 25 Feb 2021 21:24:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF94B64EC8 for ; Thu, 25 Feb 2021 21:24:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234081AbhBYVYa (ORCPT ); Thu, 25 Feb 2021 16:24:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233960AbhBYVY2 (ORCPT ); Thu, 25 Feb 2021 16:24:28 -0500 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 687A9C06174A for ; Thu, 25 Feb 2021 13:23:48 -0800 (PST) Received: by mail-wr1-x433.google.com with SMTP id e10so6410509wro.12 for ; Thu, 25 Feb 2021 13:23:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=uxVQ1dg2nqhX8SNUvSx/CFwCMMBlF2nfp3347F+VDtY=; b=PAAxWsfRQaqHyQHVBsZcTfsHYcam3D/lZHov192trhSuyuWHOeTHssyDHro6GZ1m41 +mFE0/jr5ucIxRTGCDmwunY1W8iaG9fuzEefRedUsYYuaPrTLEI/X3eWfpsK5/RDUPGl bp9CJuDtTl/UGLYsNHOZ3+vffNr/sHgqxTY/igHpqQySJlkauOjkWwZvVCdvtvSYK8Wb D7RopBFC/jUAbbN0h+F4tcvb1LsvYNuM5O9SrOfPClwaY0AqdO1xWYJrok9bL4NCqSSC DklWYigl3CEN2MFsqscOCRCg5Q6dsdiBEm8DGC2rOOAVWwP3pvsR3ugKKt9sopmhTSB0 hLEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=uxVQ1dg2nqhX8SNUvSx/CFwCMMBlF2nfp3347F+VDtY=; b=srB1XGw5m6tLlcneYMW+OstP/ylp5+S97ISM/xGGcfEPQeXqd5Z2MuC43TJnMXNPpc s7jwFG/YXHkyL3VewVQSPnvI8FWTPZRODTCrTRQMvvNNl5l7a8ASEvpIOUyzmFCIPgeU Tl1CXpaedZD80MbGOTkyk2I9DfGh+SMIii4TOX5aBNpuOauu8JNVnpOGGF01TKyjKMw7 A3HZuYGKg6pEt+jkOnd1KdfrdKiG/72eQ4nyfUp5QksIJlMCVXPfysT92boWe18Cnj07 CM9tKlZmD3g1o+/uI6MNgk5TxD0iEVqFG5uCrLf285dNZ470M1XhpX4p2z6fjyaWS3sP lRYg== X-Gm-Message-State: AOAM5304hH6n8MKwkgy4v7vf6d1698VXQDN5+Kyzq1Qgxm5YswGZZwmq GY6NYxKoH9kduqtru8ACIxM= X-Google-Smtp-Source: ABdhPJzQ5YlLo33xI6bURCHVBnHZRYD+YCCLimQibZKvpvL7oBafeaEZweIqce9eJPt5giT5vq/Vcg== X-Received: by 2002:adf:f841:: with SMTP id d1mr5322608wrq.36.1614288227234; Thu, 25 Feb 2021 13:23:47 -0800 (PST) Received: from debian (host-2-98-59-96.as13285.net. [2.98.59.96]) by smtp.gmail.com with ESMTPSA id n186sm8854440wmn.22.2021.02.25.13.23.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Feb 2021 13:23:46 -0800 (PST) Date: Thu, 25 Feb 2021 21:23:44 +0000 From: Sudip Mukherjee To: gregkh@linuxfoundation.org Cc: dan.j.williams@intel.com, colyli@suse.com, dave.jiang@intel.com, ira.weiny@intel.com, rpalethorpe@suse.com, stable@vger.kernel.org, vishal.l.verma@intel.com Subject: Re: FAILED: patch "[PATCH] libnvdimm/dimm: Avoid race between probe and" failed to apply to 4.19-stable tree Message-ID: References: <1612779897191109@kroah.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="KFEKECFtOqNiUDDD" Content-Disposition: inline In-Reply-To: <1612779897191109@kroah.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org --KFEKECFtOqNiUDDD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Greg, On Mon, Feb 08, 2021 at 11:24:57AM +0100, gregkh@linuxfoundation.org wrote: > > The patch below does not apply to the 4.19-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to . Here is the backport. Will apply to all branches till 4.4-stable. -- Regards Sudip --KFEKECFtOqNiUDDD Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="0001-libnvdimm-dimm-Avoid-race-between-probe-and-availabl.patch" >From 49a07391dd8bef6e40bb44ca5636dd429f86e81a Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 1 Feb 2021 16:20:40 -0800 Subject: [PATCH] libnvdimm/dimm: Avoid race between probe and available_slots_show() commit 7018c897c2f243d4b5f1b94bc6b4831a7eab80fb upstream Richard reports that the following test: (while true; do cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null done) & while true; do for i in $(seq 0 4); do echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind done for i in $(seq 0 4); do echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind done done ...fails with a crash signature like: divide error: 0000 [#1] SMP KASAN PTI RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm] [..] Call Trace: available_slots_show+0x4e/0x120 [libnvdimm] dev_attr_show+0x42/0x80 ? memset+0x20/0x40 sysfs_kf_seq_show+0x218/0x410 The root cause is that available_slots_show() consults driver-data, but fails to synchronize against device-unbind setting up a TOCTOU race to access uninitialized memory. Validate driver-data under the device-lock. Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure") Cc: Cc: Vishal Verma Cc: Dave Jiang Cc: Ira Weiny Cc: Coly Li Reported-by: Richard Palethorpe Acked-by: Richard Palethorpe Signed-off-by: Dan Williams [sudip: use device_lock()] Signed-off-by: Sudip Mukherjee --- drivers/nvdimm/dimm_devs.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c index 863cabc35215..f0e0e3b42c91 100644 --- a/drivers/nvdimm/dimm_devs.c +++ b/drivers/nvdimm/dimm_devs.c @@ -359,16 +359,16 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RO(state); -static ssize_t available_slots_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t __available_slots_show(struct nvdimm_drvdata *ndd, char *buf) { - struct nvdimm_drvdata *ndd = dev_get_drvdata(dev); + struct device *dev; ssize_t rc; u32 nfree; if (!ndd) return -ENXIO; + dev = ndd->dev; nvdimm_bus_lock(dev); nfree = nd_label_nfree(ndd); if (nfree - 1 > nfree) { @@ -380,6 +380,18 @@ static ssize_t available_slots_show(struct device *dev, nvdimm_bus_unlock(dev); return rc; } + +static ssize_t available_slots_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + ssize_t rc; + + device_lock(dev); + rc = __available_slots_show(dev_get_drvdata(dev), buf); + device_unlock(dev); + + return rc; +} static DEVICE_ATTR_RO(available_slots); static struct attribute *nvdimm_attributes[] = { -- 2.30.0 --KFEKECFtOqNiUDDD--