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 251BAC433FE for ; Mon, 14 Nov 2022 01:25:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235085AbiKNBZY (ORCPT ); Sun, 13 Nov 2022 20:25:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230525AbiKNBZX (ORCPT ); Sun, 13 Nov 2022 20:25:23 -0500 Received: from mail-oo1-xc29.google.com (mail-oo1-xc29.google.com [IPv6:2607:f8b0:4864:20::c29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D36FE10067 for ; Sun, 13 Nov 2022 17:25:22 -0800 (PST) Received: by mail-oo1-xc29.google.com with SMTP id j6-20020a4ab1c6000000b004809a59818cso1411578ooo.0 for ; Sun, 13 Nov 2022 17:25:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=uQKxccK98/K9VJcoGVJq2IDRGQmIt84pMQmm74SS1W8=; b=ZOO9S6HIL5APN2+tibYbQvxC7VESX0LWx4QIC5VBNAxlEGIslKK+3ljSERnrO8uLKc XdsM4HcfHvApJS19bVt7hLd5hgZ95+gXPUK2fPMzw2jY04Xhnu8tn4AiF98NASdYrnqb ekKXkAxeyFrB94GvjQOtIpcA96NE0wVD32MGmMZ7bLTEJMZAPafl805pw1xzsZnUq8qR SVC4+MJVaMFYn0KSDGfLlfvWzi+MjRRuNh3/k0P2ZYs8mG3YbH4RmcwX+WeUbTpDPzE6 NCl4tJOkn3ns88WwGDy6t1QyVJ/LnMUiTJpVjE0O4zbhjigveApmp8laOOAj1+w+IBVt HdtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uQKxccK98/K9VJcoGVJq2IDRGQmIt84pMQmm74SS1W8=; b=V8FOgwEj2LMH8z+4IFFrYrodHm75tcSAfv7PB6RPT+6FU4O/ut7Qe1bqjcji/QMIMA k6Cr3qeHh91yLSthVr9fP+rjF4m8DewUuupTLVGkmkpap+8sA4sKfwsiLl5ffKIIrBHw t78oH9rkeJ38k2zPB83lXWxcGKSCjRSNEXCOEWYeFbEVSdYw2N2+/Y9rY+tCkygDtxyv FqI1UPMY/XkWOQkYSSmI6JsrJe/CiaAK7NACX1Nps/4BVUYeou4TWisPK3ZR4QAVPiIg eXoCs9ycnA3tL3vdV326jCkZhjirAB7ct6erKPEZlugMNih66wRVd7uUCuZA+3SLXVB0 GITQ== X-Gm-Message-State: ANoB5pm8jSFfESE38rWoeCGtqGP+O1CK2LFBK4w1wm+iHS5kishdLuqe CJOWTsbKMUebezb/SB6rcbt2iHegb9o= X-Google-Smtp-Source: AA0mqf6J5R8Q9cqmAIO6kQcMebWk6tpsVq50ey/lmBSlEw9ckYROxglXI52ugJz5rBZsyc6irjP0QQ== X-Received: by 2002:a4a:95cb:0:b0:481:1274:b65c with SMTP id p11-20020a4a95cb000000b004811274b65cmr4736768ooi.6.1668389122180; Sun, 13 Nov 2022 17:25:22 -0800 (PST) Received: from localhost ([2600:1700:65a0:ab60:6343:42bb:5d9b:dded]) by smtp.gmail.com with ESMTPSA id a19-20020a056808129300b00359f96eeb47sm3069431oiw.49.2022.11.13.17.25.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Nov 2022 17:25:21 -0800 (PST) Date: Sun, 13 Nov 2022 17:25:20 -0800 From: Cong Wang To: mingkun bian Cc: netdev@vger.kernel.org Subject: Re: [ISSUE] suspicious sock leak Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Nov 13, 2022 at 06:22:22PM +0800, mingkun bian wrote: > Hi, > > bpf map1: > key: cookie > value: addr daddr sport dport cookie sock* > > bpf map2: > key: sock* > value: addr daddr sport dport cookie sock* So none of them is sockmap? Why not use sockmap which takes care of sock refcnt for you? > > 1. Recv a "HTTP GET" request in user applicatoin > map1.insert(cookie, value) > map2.insert(sock*, value) > > 1. kprobe inet_csk_destroy_sock: > sk->sk_wmem_queued is 0 > sk->sk_wmem_alloc is 4201 > sk->sk_refcnt is 2 > sk->__sk_common.skc_cookie is 173585924 > saddr daddr sport dport is 192.168.10.x 80 > > 2. kprobe __sk_free > can not find the "saddr daddr sport dport 192.168.10.x 80" in kprobe __sk_free > > 3. kprobe __sk_free > after a while, "kprobe __sk_free" find the "saddr daddr sport dport > 127.0.0.1 xx"' info > value = map2.find(sock*) > value1 = map1.find(sock->cookie) > if (value) { > map2.delete(sock) //print value info, find "saddr daddr sport > dport" is "192.168.10.x 80“， and value->cookie is 173585924, which is > the same as "192.168.10.x 80" 's cookie. > } > > if (value1) { > map1.delete(sock->cookie) > } > > Here is my test flow, commented lines represents that sock of ”saddr > daddr sport dport 192.168.10.x 80“ does not come in __sk_free， but it > is reused by ” saddr daddr sport dport 127.0.0.1 xx" I don't see this is a problem yet, the struct sock may be still referenced by the kernel even after you close its corresponding struct socket from user-space. And TCP sockets have timewait too, so... I suggest you try sockmap to store sockets instead. Thanks.