From owner-freebsd-hackers@freebsd.org Wed Aug 7 09:11:48 2019 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 558E7C3FFB for ; Wed, 7 Aug 2019 09:11:48 +0000 (UTC) (envelope-from brightiup.zhuo@gmail.com) Received: from mail-ot1-x329.google.com (mail-ot1-x329.google.com [IPv6:2607:f8b0:4864:20::329]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 463Qjv1zw9z4RdZ for ; Wed, 7 Aug 2019 09:11:47 +0000 (UTC) (envelope-from brightiup.zhuo@gmail.com) Received: by mail-ot1-x329.google.com with SMTP id l15so101504780otn.9 for ; Wed, 07 Aug 2019 02:11:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=OG+HE4rIZwho1uojBOIh96XLzh/T1wSKhDALKZGV8C8=; b=Hg8Vd5kbllb2NDTpEUpbhs+qqKaTu16mJ/ePB/R34U5JRPc2apix9kznug1808wttj DiWK5ctzoeFFO0GNZX19mZLXf0aClGPvkthnTmE64hH3mMoEcqr0rR3hFp7byq70K+Fm zb+h7BE7/NkE/a+O9Bo+bqvp1L8H8uFvNGMPhFfHLE2wUejhiOVLVO79r99cJFeD2UO7 eAZneyOkMlN3qnz+WzO3Ie7lsR1+IBwIhmM8lgCdaie0VMRWSMiFd47oUmqsm5IBTp+n lOTaJSA3f8MQRXfIsi3iogYG1t6MqC03xUON7Gpru/k89BdpF5DMmTL9dvBFwdwYPFsT pRCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=OG+HE4rIZwho1uojBOIh96XLzh/T1wSKhDALKZGV8C8=; b=czAFv1CLeREL52PbYW3X+B1tc28MZ1aKplT0WPQAjxAQ/s26pkKxXlhvbG5Rt4UT84 L1Lb+7nmS2ukfVNa5DzsYANSEP/C/VPRj6vG1z+UfipmhhiG0uShVfHUS8lnx67rahrt aF4bLlx0tkiAjCtJZVAoizFHxgYu2jCBPRjpF9T58vdED4Xt762vsmS2mGTbWTUUR312 kDVRqLVkk110A5eXVzHMkQGqVDZ+9+UOirHxd3E9kNJHldE/RptrssAwvDMqGzEVAv3k HPeBe6CkZl3kan3435x7VOu5rcxWS5MZEKhLEzXGgOuEolawdoEkbAqmt/lpvNrTZuE9 gO8A== X-Gm-Message-State: APjAAAXgkOrjCMf7fyrI1IaEw/V/R700N2SWmFJ/JAFyYAFvF3tcve7L 464UZ7JbLTn/80a8NqoeKrF5ZJt2cOJmSrCcsByXGniBHpnMbA== X-Google-Smtp-Source: APXvYqwr30TUIpvVBz5c5Vp/h8JgaUQ3aHgmSO1kWT6E6ZX9dRUgg+V7Jzfxk+CnCCVn16ufqt5oaV2MxRtUHS7nJlk= X-Received: by 2002:a6b:6505:: with SMTP id z5mr8120989iob.295.1565169105499; Wed, 07 Aug 2019 02:11:45 -0700 (PDT) MIME-Version: 1.0 From: Liang Zhuo Date: Wed, 7 Aug 2019 17:11:34 +0800 Message-ID: Subject: Force kernel epoch calls To: freebsd-hackers@freebsd.org X-Rspamd-Queue-Id: 463Qjv1zw9z4RdZ X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=Hg8Vd5kb; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of brightiupzhuo@gmail.com designates 2607:f8b0:4864:20::329 as permitted sender) smtp.mailfrom=brightiupzhuo@gmail.com X-Spamd-Result: default: False [-4.00 / 15.00]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; TO_DN_NONE(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; NEURAL_HAM_SHORT(-1.00)[-1.000,0]; FROM_EQ_ENVFROM(0.00)[]; IP_SCORE(0.00)[ip: (-9.53), ipnet: 2607:f8b0::/32(-3.04), asn: 15169(-2.45), country: US(-0.05)]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; TAGGED_FROM(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com.dwl.dnswl.org : 127.0.5.0]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; IP_SCORE_FREEMAIL(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; RCVD_IN_DNSWL_NONE(0.00)[9.2.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Aug 2019 09:11:48 -0000 Hi list, I have a problem with *epoch* while I am trying to write an exploit of a FreeBSD kernel bug. Specifically, many schedules are managed by epoch system, like *if_d\* *estroy()* which destroys a *struct ifnet* object, and *in_pcbfree_**defered()* which destroys a *struct inpcb* object. My question is that these schedules will only be called just before the process exits by *epoch_call_task() *as follow: fork_exit() -> gtaskqueue_thread_loop() -> gtaskqueue_run_locked() -> epoch_call_task() -> if_destroy()/in_pcbfree_defered() But I need to control the time of freeing of those objects as better as synchronization. Do do I have any methods to force these calls in epoch system to be called in userspace? Thanks, Brightiup