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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 4EEABC432C0 for ; Mon, 18 Nov 2019 12:25:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20BCA206F4 for ; Mon, 18 Nov 2019 12:25:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574079931; bh=y8W5feSYOVMmL55Boge+mPkAhCKFugFyDbqQ6R06rsU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=u8531j8g9pJVS0Ip6snBfjIskSDoZojeshg6ih/29uXf2r3SuKhKc1fwutGm8H7cb N9k+h2ErgERx68yReJB71xegA4SHUCsq2VnqeEt1/rF589hUkUnaFdeGk4pitRLkfs HvzCpHSV6gerMsQG9XLP1pMWtAPw2vc+63jy6KVE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726686AbfKRMZa (ORCPT ); Mon, 18 Nov 2019 07:25:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:49878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726464AbfKRMZa (ORCPT ); Mon, 18 Nov 2019 07:25:30 -0500 Received: from localhost (unknown [5.29.147.182]) (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 A9DED206F4; Mon, 18 Nov 2019 12:25:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574079929; bh=y8W5feSYOVMmL55Boge+mPkAhCKFugFyDbqQ6R06rsU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kTh9opAOXXWRpftwT/ZnZynNfstlUe23LXkGF0vVrwkrGVWnDNcbUKlNHVzRaBFOQ qX74nDTEYluD+MlPOTHc5cLPLQgvLjoXYUfxGf+DI8bB7i7nIrRVeln/5qybz+tkbX HVDaRCiT6RcoPMHdg/WjBfjNh4oEMaGj7jedoEc8= Date: Mon, 18 Nov 2019 14:25:26 +0200 From: Leon Romanovsky To: jouni.hogander@unikie.com Cc: netdev@vger.kernel.org, David Miller , Greg Kroah-Hartman , Lukas Bulwahn Subject: Re: [PATCH v3] net-sysfs: Fix reference count leak Message-ID: <20191118122526.GB52766@unreal> References: <20191118120650.12597-1-jouni.hogander@unikie.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191118120650.12597-1-jouni.hogander@unikie.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Nov 18, 2019 at 02:06:50PM +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. > > Drivers are supposed to call free_netdev in case of error. In non-error > case the last reference is given up there and device release sequence > is triggered. In error case this reference is kept and the release > sequence is never started. > > Fix this reference count leak by allowing giving up the reference also > in error case in free_netdev. > > Also replace BUG_ON with WARN_ON in free_netdev and in netdev_release. > > 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 > > v2 -> v3: > * Replaced BUG_ON with WARN_ON in free_netdev and netdev_release > > v1 -> v2: > * Relying on driver calling free_netdev rather than calling > put_device directly in error path This changelog should go after "---" line. Thanks