From owner-svn-src-all@FreeBSD.ORG Sun Nov 2 19:21:02 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D4C74E70; Sun, 2 Nov 2014 19:21:02 +0000 (UTC) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 418349B7; Sun, 2 Nov 2014 19:21:01 +0000 (UTC) Received: from tom.home (kostik@localhost [127.0.0.1]) by kib.kiev.ua (8.14.9/8.14.9) with ESMTP id sA2JKvwN015038 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 2 Nov 2014 21:20:57 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.9.2 kib.kiev.ua sA2JKvwN015038 Received: (from kostik@localhost) by tom.home (8.14.9/8.14.9/Submit) id sA2JKvKt015037; Sun, 2 Nov 2014 21:20:57 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sun, 2 Nov 2014 21:20:57 +0200 From: Konstantin Belousov To: Adrian Chadd Subject: Re: svn commit: r273958 - head/sys/dev/random Message-ID: <20141102192057.GB53947@kib.kiev.ua> References: <201411020201.sA221unt091493@svn.freebsd.org> <720EB74E-094A-43F3-8B1C-47BC7F6FECC3@grondar.org> <1414934579.17308.248.camel@revolution.hippie.lan> <6FB65828-6A79-4BDE-A9F7-BC472BA538CE@grondar.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on tom.home Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , Ian Lepore , Mark R V Murray X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Nov 2014 19:21:03 -0000 On Sun, Nov 02, 2014 at 11:05:27AM -0800, Adrian Chadd wrote: > [snip all the conversation] > > Ok. There's still a problem that I can trigger by trying to Ctrl-C a > process that's blocked reading for randomness. I'll try to chase up > more details about and file a PR about it. > > The unfortunate part is that the kernel side stack trace of the > offending / hung process isn't currently helpful. :( > >From what I see, signals are essentially ignored in the read code. See random_adaptors.c:random_adaptor_read(): /* Sleep instead of going into a spin-frenzy */ tsleep(&random_adaptor, PUSER | PCATCH, "block", hz/10); The error which would indicate the signal catch, is dropped. Also, unbound sleep does not drop random_adaptor_lock, which means that you cannot module which could provide some more randomness for you, while any thread is stuck in read loop.