From owner-freebsd-hackers@freebsd.org Wed Aug 7 16:58:12 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 58C87B0DA7 for ; Wed, 7 Aug 2019 16:58:12 +0000 (UTC) (envelope-from hps@selasky.org) Received: from mail.turbocat.net (turbocat.net [IPv6:2a01:4f8:c17:6c4b::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 463d4324wzz40xM for ; Wed, 7 Aug 2019 16:58:10 +0000 (UTC) (envelope-from hps@selasky.org) Received: from hps2016.home.selasky.org (unknown [62.141.129.235]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 46669260195; Wed, 7 Aug 2019 18:58:07 +0200 (CEST) Subject: Re: Force kernel epoch calls To: Liang Zhuo Cc: freebsd-hackers@freebsd.org References: From: Hans Petter Selasky Message-ID: Date: Wed, 7 Aug 2019 18:57:27 +0200 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 463d4324wzz40xM X-Spamd-Bar: ----- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of hps@selasky.org designates 2a01:4f8:c17:6c4b::2 as permitted sender) smtp.mailfrom=hps@selasky.org X-Spamd-Result: default: False [-5.87 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+a:mail.turbocat.net:c]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[selasky.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_SHORT(-1.00)[-0.999,0]; RCPT_COUNT_TWO(0.00)[2]; IP_SCORE(-2.57)[ip: (-9.10), ipnet: 2a01:4f8::/29(-1.94), asn: 24940(-1.82), country: DE(-0.01)]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:24940, ipnet:2a01:4f8::/29, country:DE]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] 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 16:58:12 -0000 On 2019-08-07 11:56, Liang Zhuo wrote: > Thanks for the quick reply. > > Actually, I just need some tricks > in *userspace *to force the kernel to > call those callbacks or some methods > which could inform the kernel to call > the callbacks. > > I am not writing a driver or kernel patch, > it's just a userspace program which could > escalate privilege to root. > > Thanks, > Brightiup Hi, If you want to force these callbacks, you'll need to iterate over all the CPU's and do: GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task)); --HPS