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 99331C433F5 for ; Thu, 19 May 2022 05:36:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234008AbiESFgX (ORCPT ); Thu, 19 May 2022 01:36:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229833AbiESFgU (ORCPT ); Thu, 19 May 2022 01:36:20 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 987C52982D for ; Wed, 18 May 2022 22:36:18 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id k17-20020a252411000000b0064ea6c388baso2727125ybk.0 for ; Wed, 18 May 2022 22:36:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=+mOeU0zYyZNrut5u+oizuXhzDSBpVolUtmDQznpEMWY=; b=Lof6YSPulz06XaUmNrUy0S7pXdV6ehb+LARBONQnDxR9M9zg9jXWhZ8hCJZmQf8s9f v+25Szh4he0Bky19+3CVNKakFy65IR7KO0+jB+Ex/vItcV9RwbVbvjH2A5e2/OE/x4k4 N55kjd827z4uYRiC+/sV8O/PtldTZzs+8eq6kSg/ytpAhebqCQI17u4vZ1h3u8huxetw uqcVnmwyGecNdoS9OkxrC8SiIu9G3KQyqUPN6oavhb6RxpAcvEJyHFyvviq2HH+eNrRJ MJ29LdBxKOOFwOHXkXlpHnm2GegaoZzvXBLyAvl9p9vQ3+h0UqXiggjjlAfXkgG2JJr3 CMfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=+mOeU0zYyZNrut5u+oizuXhzDSBpVolUtmDQznpEMWY=; b=7UMxdXJZld8UfscG8waKE1J6ZgL9uLc13+TPVkEIid+HsszX/H6LCq1mvkk0oyPsu7 EWktmtBC/HQs8t68EfKy2NAO5+L+fsXBSvgrBntqpDV4JtXfmW/ktsFSId64m0dr63sM mcl4khkuMjxKhrDokb0zOILcCBPFPSbNeCPAAwgPPIutTUijLQGvhAJ7noLPTPa4bAl2 Bs5HLeFJgZXQkaxQhcc4LjheU7kRiuXDSzv+/X7UIWye7YMySaVRCJS/4beuwpXa8qcA aftoBqHKK1sG9RTBpDtwKyUu5OPZ+bVEc4vgxTi85LReCr1lnuJ6nbFVfqR8SE7w82VQ 7jNA== X-Gm-Message-State: AOAM532gFreP492MmHeQAlFg7Zd8s7YCSwb0TpPjfNrEVUMM77FV6aNw BAj6d0STzxwR/eETesDh1qflcp/mGebdNw== X-Google-Smtp-Source: ABdhPJwbIxmVNXNi5PAO0LjjYUs6ekZ3dNU6Pl9cHr6CHypPt7Y1BaKjX5Y+Xl8T522BNsfZhbLJlHsqNDB1rA== X-Received: from shakeelb.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:28b]) (user=shakeelb job=sendgmr) by 2002:a5b:dcd:0:b0:64e:2365:69a8 with SMTP id t13-20020a5b0dcd000000b0064e236569a8mr2660064ybr.254.1652938577861; Wed, 18 May 2022 22:36:17 -0700 (PDT) Date: Thu, 19 May 2022 05:36:15 +0000 In-Reply-To: <20220517164713.4610-1-kristen@linux.intel.com> Message-Id: <20220519053615.zqwecsooceqzwjdf@google.com> Mime-Version: 1.0 References: <20220517164713.4610-1-kristen@linux.intel.com> Subject: Re: [PATCH] x86/sgx: Set active memcg prior to shmem allocation From: Shakeel Butt To: Kristen Carlson Accardi Cc: linux-sgx@vger.kernel.org, Jarkko Sakkinen , Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 17, 2022 at 09:47:13AM -0700, Kristen Carlson Accardi wrote: > [...] > +int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index, > + struct sgx_backing *backing) > +{ > + struct mem_cgroup *old_memcg; > + int ret; > + > + old_memcg = sgx_encl_set_active_memcg(encl); This function is leaking memcg reference. Please change sgx_encl_set_active_memcg() to sgx_encl_get_mem_cgroup() or something which will return the memcg with the refcount elevated. Then use set_active_memcg(returned_memcg) here. > + > + ret = sgx_encl_get_backing(encl, page_index, backing); > + > + set_active_memcg(old_memcg); mem_cgroup_put(returned_memcg) here. > + > + return ret; > +}