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=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 04FD5C47423 for ; Fri, 25 Sep 2020 15:18:05 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9576A20878 for ; Fri, 25 Sep 2020 15:18:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="uts/Hgs6"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="0I0jvTv7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9576A20878 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=nA2xEXdIRYf/oCvt4Flfdf0XrTQ59whlGThbMPbLly8=; b=uts/Hgs63gY9ywPHWcRn3bBxY jAqoF0Iwmjh8n0ESjUe1f0S9c2kC7QOe7hTXDLTBqQWYrkeegBqIww0mW3FgBDLZAm38PByCXLeKK ldbyOD5NbleciEemSp1w6jISMrAxAUzODO/pQXqcP/7g0jWQBi3eqX0ds3mTMX8FUf/ey60IpHL5r P3KpV3ittQyHVbgtBiZGpG6eoBBk0JvOOqJom+aaxfwWI/OulLy5sRBNkktn6bv1QRGiEyMmsHCWs sV0eC/M8Zx3cjnFV5CbP1C3mYkLRvATuRp6Qchp7YDRDQSiCvDWqOFCUD07KvT5ByeZmV/4n72Af2 PBBFe9FtQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLpU1-0005c7-NQ; Fri, 25 Sep 2020 15:18:01 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLpTz-0005bT-2X for linux-nvme@lists.infradead.org; Fri, 25 Sep 2020 15:17:59 +0000 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B44E920878; Fri, 25 Sep 2020 15:17:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601047078; bh=Memmat2QMSKm4nwC6E/N+LYsT2VSLAWg4jqrX9rOxRc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0I0jvTv72ihg9+bzMure3BX1lc+87CO5bL9392leVtXnedqMSe5ygE5G4jcX2w1qW xoHSyqw+O8y4wGORU/iFtjKf17BUhMzTBzKdn1CSNW/QQG4RWwA0fbFWc2yeKlC8z5 AE3L4akyOt44u/YxCsUo0F4LAURd4D62LpCDsAXE= Date: Fri, 25 Sep 2020 17:18:12 +0200 From: Greg KH To: Coly Li Subject: Re: [PATCH v8 1/7] net: introduce helper sendpage_ok() in include/linux/net.h Message-ID: <20200925151812.GA3182427@kroah.com> References: <20200925150119.112016-1-colyli@suse.de> <20200925150119.112016-2-colyli@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200925150119.112016-2-colyli@suse.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200925_111759_245498_7EC736E8 X-CRM114-Status: GOOD ( 26.16 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Vlastimil Babka , Chaitanya Kulkarni , linux-scsi@vger.kernel.org, netdev@vger.kernel.org, Philipp Reisner , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Mikhail Skorzhinskii , linux-block@vger.kernel.org, Hannes Reinecke , Jan Kara , stable@vger.kernel.org, ceph-devel@vger.kernel.org, open-iscsi@googlegroups.com, Christoph Hellwig , Sagi Grimberg Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Sep 25, 2020 at 11:01:13PM +0800, Coly Li wrote: > The original problem was from nvme-over-tcp code, who mistakenly uses > kernel_sendpage() to send pages allocated by __get_free_pages() without > __GFP_COMP flag. Such pages don't have refcount (page_count is 0) on > tail pages, sending them by kernel_sendpage() may trigger a kernel panic > from a corrupted kernel heap, because these pages are incorrectly freed > in network stack as page_count 0 pages. > > This patch introduces a helper sendpage_ok(), it returns true if the > checking page, > - is not slab page: PageSlab(page) is false. > - has page refcount: page_count(page) is not zero > > All drivers who want to send page to remote end by kernel_sendpage() > may use this helper to check whether the page is OK. If the helper does > not return true, the driver should try other non sendpage method (e.g. > sock_no_sendpage()) to handle the page. > > Signed-off-by: Coly Li > Cc: Chaitanya Kulkarni > Cc: Christoph Hellwig > Cc: Hannes Reinecke > Cc: Jan Kara > Cc: Jens Axboe > Cc: Mikhail Skorzhinskii > Cc: Philipp Reisner > Cc: Sagi Grimberg > Cc: Vlastimil Babka > Cc: stable@vger.kernel.org > --- > include/linux/net.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/include/linux/net.h b/include/linux/net.h > index d48ff1180879..05db8690f67e 100644 > --- a/include/linux/net.h > +++ b/include/linux/net.h > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > #include > > #include > @@ -286,6 +287,21 @@ do { \ > #define net_get_random_once_wait(buf, nbytes) \ > get_random_once_wait((buf), (nbytes)) > > +/* > + * E.g. XFS meta- & log-data is in slab pages, or bcache meta > + * data pages, or other high order pages allocated by > + * __get_free_pages() without __GFP_COMP, which have a page_count > + * of 0 and/or have PageSlab() set. We cannot use send_page for > + * those, as that does get_page(); put_page(); and would cause > + * either a VM_BUG directly, or __page_cache_release a page that > + * would actually still be referenced by someone, leading to some > + * obscure delayed Oops somewhere else. > + */ > +static inline bool sendpage_ok(struct page *page) > +{ > + return !PageSlab(page) && page_count(page) >= 1; Do you have one extra ' ' after "return" there? And this feels like a mm thing, why put it in net.h and not mm.h? thanks, greg k-h _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme