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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87DE9C433FE for ; Wed, 2 Nov 2022 18:03:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229700AbiKBSDd (ORCPT ); Wed, 2 Nov 2022 14:03:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231627AbiKBSDQ (ORCPT ); Wed, 2 Nov 2022 14:03:16 -0400 Received: from mail-yw1-x1131.google.com (mail-yw1-x1131.google.com [IPv6:2607:f8b0:4864:20::1131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43CB92EF39 for ; Wed, 2 Nov 2022 11:03:15 -0700 (PDT) Received: by mail-yw1-x1131.google.com with SMTP id 00721157ae682-37063f855e5so87452507b3.3 for ; Wed, 02 Nov 2022 11:03:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=TZ+dLjoYm09HSwY2V625UBoDfQUrFrbVVtB8huuIfFI=; b=AGksGsxycKU0pz7YGhRbwj2Iojk6QuhT7MKrH3A54CQzhF11pu+owlFVD+BOsAMKWi 2uKu0k2uauNRvZuCpakhRq0ZWFyLW+ty0mlMEH8nz0+oRY2Vvz4izXaXUld6Wrd+tY1n JKnFsLrXniOFttFffAIWvS1enZyTEZrRjlne1CM14wmMOCHXUWhlP3WlQ+I/3sruJXlz ssmaENl4smV9KLqONOmdzvMtk9lFuvWdy22gLYHch7q8vJjFLb2W0ykcjm64xfLPi0lJ 4eUiK2fVWwl9v4Z3IeygH+DKoRppTTk/yXdv/ylHAJ3HEqwyYj0/90vM+aGjQICmommR wgIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=TZ+dLjoYm09HSwY2V625UBoDfQUrFrbVVtB8huuIfFI=; b=JIpYIZEkQK2EUJXaRQzuaOegjlhcGVTUk5mfHa2eLYGKdwLH4YnEWNu+8ePHY+/lqq wEjZOLCZ7wwHyWN86mMrVbICe0xq7tPNkyonvb74a+rlpsIzU+7N5oY21Itv15nlOF5s ZV/GanMVUouxZTj9+JsjQNCLuXKNcG1ndRQ92fnI38PzKe2Q3m1LQsXJwsza4KH4bPu+ zAyQ0F8uNmb97WZXgra67sJF0RjUEShBzauyTTp9mniaJ0FU+OSdEoHD7zoZGHGBhJ0A oey3RBRlNC86zBXq40AFIWV+WGqvdatPpAkrsqsltnMzMRuYn1NI877cizlPA9808sYL 0i3Q== X-Gm-Message-State: ACrzQf3YnIZgPrK+8ivC6HzTPQ8LuEZavO3V1oXFerCIghkAsZTFzfDG 8DLm/ESOBZ36xSZ2RUDaookFSF+Z4uS+DQ2dxMjS7A== X-Google-Smtp-Source: AMsMyM5Gqb6kUi17AH+BhzL0TfWF5uPqYKuMPUkJ++nMUJUlhOgg1fieoLPpuovS0RDTOJskgH/sqYJGZby0NqYzkv4= X-Received: by 2002:a81:c11:0:b0:36a:bcf0:6340 with SMTP id 17-20020a810c11000000b0036abcf06340mr24062798ywm.467.1667412194201; Wed, 02 Nov 2022 11:03:14 -0700 (PDT) MIME-Version: 1.0 References: <1667382079-6499-1-git-send-email-wangyufen@huawei.com> In-Reply-To: <1667382079-6499-1-git-send-email-wangyufen@huawei.com> From: Eric Dumazet Date: Wed, 2 Nov 2022 11:03:03 -0700 Message-ID: Subject: Re: [PATCH net v2] net: tun: Fix memory leaks of napi_get_frags To: Wang Yufen Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, peterpenkov96@gmail.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Nov 2, 2022 at 2:20 AM Wang Yufen wrote: > > kmemleak reports after running test_progs: > > unreferenced object 0xffff8881b1672dc0 (size 232): > comm "test_progs", pid 394388, jiffies 4354712116 (age 841.975s) > hex dump (first 32 bytes): > e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g..... > 00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@.............. > backtrace: > [<00000000c8f01748>] napi_skb_cache_get+0xd4/0x150 > [<0000000041c7fc09>] __napi_build_skb+0x15/0x50 > [<00000000431c7079>] __napi_alloc_skb+0x26e/0x540 > [<000000003ecfa30e>] napi_get_frags+0x59/0x140 > [<0000000099b2199e>] tun_get_user+0x183d/0x3bb0 [tun] > [<000000008a5adef0>] tun_chr_write_iter+0xc0/0x1b1 [tun] > [<0000000049993ff4>] do_iter_readv_writev+0x19f/0x320 > [<000000008f338ea2>] do_iter_write+0x135/0x630 > [<000000008a3377a4>] vfs_writev+0x12e/0x440 > [<00000000a6b5639a>] do_writev+0x104/0x280 > [<00000000ccf065d8>] do_syscall_64+0x3b/0x90 > [<00000000d776e329>] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The issue occurs in the following scenarios: > tun_get_user() > napi_gro_frags() > napi_frags_finish() > case GRO_NORMAL: > gro_normal_one() > list_add_tail(&skb->list, &napi->rx_list); > <-- While napi->rx_count < READ_ONCE(gro_normal_batch), > <-- gro_normal_list() is not called, napi->rx_list is not empty > <-- not ask to complete the gro work, will cause memory leaks in > <-- following tun_napi_del() > ... > tun_napi_del() > netif_napi_del() > __netif_napi_del() > <-- &napi->rx_list is not empty, which caused memory leaks > > To fix, add napi_complete() after napi_gro_frags(). > > Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") > Signed-off-by: Wang Yufen > --- > drivers/net/tun.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 27c6d23..07a0a61 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1976,6 +1976,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, > > local_bh_disable(); > napi_gro_frags(&tfile->napi); > + napi_complete(&tfile->napi); > local_bh_enable(); > mutex_unlock(&tfile->napi_mutex); > } else if (tfile->napi_enabled) { > -- > 1.8.3.1 > I think the intent of this code was to allow user space to send multiple packets to GRO layer for test purposes. (Check that GRO can aggregate multiple MSS, with respect of standard GRO rules) This fix might break some tests, but they can be updated if needed (using /sys/class/net/xxx/gro_flush_timeout) Reviewed-by: Eric Dumazet