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=-8.3 required=3.0 tests=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,USER_AGENT_SANE_1 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 250B0C432C3 for ; Fri, 15 Nov 2019 15:24:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF7582073A for ; Fri, 15 Nov 2019 15:24:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573831462; bh=abL67/1fMt2ab5egyITGAgwmpW4pz8+D963330VfvTk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=phaOleiw8OKs7J7jcL7vZbvsy+qxjcTUN7tZT2WWvfKN83CKR+FuUruRufRF0uuBX VsIryN8YFAUt+mxpXWRuG0Wlz75pJ0fIxQQt8q4RO/bGTa6hcDFbnaoY0U5/p3v4UY 6n4DEJXmSj/6tAwhVigpr4VFhS2IFGiPYt32Q+p0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727588AbfKOPYU (ORCPT ); Fri, 15 Nov 2019 10:24:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:40310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727531AbfKOPYU (ORCPT ); Fri, 15 Nov 2019 10:24:20 -0500 Received: from localhost (unknown [122.147.212.193]) (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 24F2720732; Fri, 15 Nov 2019 15:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573831458; bh=abL67/1fMt2ab5egyITGAgwmpW4pz8+D963330VfvTk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HBEKeI52QXxkGIqW2JjKAmlymlFFbeUjGQ4w/JeO8a8cFaIV2gh+wl4mb8Ju7TYtu QbepAeD4NczVeM21Pjyr/v0V4j5kyPrbnu1h023h6g6pSnY3X8fAUfgIPZwPpH+s6e jd6mN6c3E3WWtQpNT7Mqss7ZKtaYOppO9IYBKM2E= Date: Fri, 15 Nov 2019 23:24:16 +0800 From: Greg Kroah-Hartman To: jouni.hogander@unikie.com Cc: netdev@vger.kernel.org, David Miller , Lukas Bulwahn Subject: Re: [PATCH] net-sysfs: Fix reference count leak Message-ID: <20191115152416.GA377478@kroah.com> References: <20191115122412.2595-1-jouni.hogander@unikie.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191115122412.2595-1-jouni.hogander@unikie.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Nov 15, 2019 at 02:24:12PM +0200, jouni.hogander@unikie.com wrote: > From: Jouni Hogander > > Netdev_register_kobject is calling device_initialize. In case of error > reference taken by device_initialize is not given up. This is > the rootcause for couple of memory leaks reported by Syzkaller: > > BUG: memory leak unreferenced object 0xffff8880675ca008 (size 256): > comm "netdev_register", pid 281, jiffies 4294696663 (age 6.808s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<0000000058ca4711>] kmem_cache_alloc_trace+0x167/0x280 > [<000000002340019b>] device_add+0x882/0x1750 > [<000000001d588c3a>] netdev_register_kobject+0x128/0x380 > [<0000000011ef5535>] register_netdevice+0xa1b/0xf00 > [<000000007fcf1c99>] __tun_chr_ioctl+0x20d5/0x3dd0 > [<000000006a5b7b2b>] tun_chr_ioctl+0x2f/0x40 > [<00000000f30f834a>] do_vfs_ioctl+0x1c7/0x1510 > [<00000000fba062ea>] ksys_ioctl+0x99/0xb0 > [<00000000b1c1b8d2>] __x64_sys_ioctl+0x78/0xb0 > [<00000000984cabb9>] do_syscall_64+0x16f/0x580 > [<000000000bde033d>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > [<00000000e6ca2d9f>] 0xffffffffffffffff > > BUG: memory leak > unreferenced object 0xffff8880668ba588 (size 8): > comm "kobject_set_nam", pid 286, jiffies 4294725297 (age 9.871s) > hex dump (first 8 bytes): > 6e 72 30 00 cc be df 2b nr0....+ > backtrace: > [<00000000a322332a>] __kmalloc_track_caller+0x16e/0x290 > [<00000000236fd26b>] kstrdup+0x3e/0x70 > [<00000000dd4a2815>] kstrdup_const+0x3e/0x50 > [<0000000049a377fc>] kvasprintf_const+0x10e/0x160 > [<00000000627fc711>] kobject_set_name_vargs+0x5b/0x140 > [<0000000019eeab06>] dev_set_name+0xc0/0xf0 > [<0000000069cb12bc>] netdev_register_kobject+0xc8/0x320 > [<00000000f2e83732>] register_netdevice+0xa1b/0xf00 > [<000000009e1f57cc>] __tun_chr_ioctl+0x20d5/0x3dd0 > [<000000009c560784>] tun_chr_ioctl+0x2f/0x40 > [<000000000d759e02>] do_vfs_ioctl+0x1c7/0x1510 > [<00000000351d7c31>] ksys_ioctl+0x99/0xb0 > [<000000008390040a>] __x64_sys_ioctl+0x78/0xb0 > [<0000000052d196b7>] do_syscall_64+0x16f/0x580 > [<0000000019af9236>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > [<00000000bc384531>] 0xffffffffffffffff > > Reported-by: syzbot+ad8ca40ecd77896d51e2@syzkaller.appspotmail.com > Cc: David Miller > Cc: Greg Kroah-Hartman > Cc: Lukas Bulwahn > Signed-off-by: Jouni Hogander > --- > net/core/net-sysfs.c | 21 ++++++++++++++++----- > 1 file changed, 16 insertions(+), 5 deletions(-) > > diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c > index 865ba6ca16eb..72ecad583953 100644 > --- a/net/core/net-sysfs.c > +++ b/net/core/net-sysfs.c > @@ -1626,6 +1626,12 @@ static void netdev_release(struct device *d) > { > struct net_device *dev = to_net_dev(d); > > + /* Triggered by an error clean-up (put_device) during > + * initialization. > + */ > + if (dev->reg_state == NETREG_UNINITIALIZED) > + return; > + Are you sure about this? What about the memory involved here, what will free that? > BUG_ON(dev->reg_state != NETREG_RELEASED); > > /* no need to wait for rcu grace period: > @@ -1745,16 +1751,21 @@ int netdev_register_kobject(struct net_device *ndev) > > error = device_add(dev); > if (error) > - return error; > + goto err_device_add; > > error = register_queue_kobjects(ndev); > - if (error) { > - device_del(dev); > - return error; > - } > + if (error) > + goto err_register_queue_kobjects; > > pm_runtime_set_memalloc_noio(dev, true); > > + return error; > + > +err_register_queue_kobjects: > + device_del(dev); > +err_device_add: > + put_device(dev); > + > return error; > } > > -- > 2.17.1 The rest of the patch looks sane to me from a "uses the driver api correctly now" point of view. But I don't know the lifetime rules of the netdev structure enough to say if that check for the reg_state is correct or not. thanks, greg k-h