From owner-svn-src-head@FreeBSD.ORG Mon Nov 3 03:08:47 2014 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 959993A4; Mon, 3 Nov 2014 03:08:47 +0000 (UTC) Received: from mail-wi0-x22a.google.com (mail-wi0-x22a.google.com [IPv6:2a00:1450:400c:c05::22a]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id B3460A52; Mon, 3 Nov 2014 03:08:46 +0000 (UTC) Received: by mail-wi0-f170.google.com with SMTP id q5so5029527wiv.5 for ; Sun, 02 Nov 2014 19:08:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=o2N1Ox4emNjnNtT5SDlc6+WrNeQE+mG9VLGkxyCnsFY=; b=fp0ZMclC5/DicqLdsp5eYwblQsQp92znAKyYa6BhWudssf4ZWn0QjXj5y9IY+7LHqJ IoybzJm7Mf3eBkRYl2qPXQ6qnS39lzW2aC/P/Y6HL1Cthcsa1L/0sx7nkj/KAGGOGZtF 1/9BM8OuWAZDcaYiz16xKY/5K6m+wzqYOlBNEWy0V8R4gHHOidHE1iVaSNg9FczAnoJh T1D5oe3p4w9GGK2AYkgSQE21SuqAyqtE7/95Oh05hd1ZMVpxY4C2ED8OkMsez3i7Rals Z1nChYoVNXCI6m3beXs4pvFkmhrVm49zutK1llymqTkDmtjLtpZ7tPclt44ltwUVWyjn jBPQ== X-Received: by 10.180.78.36 with SMTP id y4mr12994266wiw.52.1414984124951; Sun, 02 Nov 2014 19:08:44 -0800 (PST) Received: from dft-labs.eu (n1x0n-1-pt.tunnel.tserv5.lon1.ipv6.he.net. [2001:470:1f08:1f7::2]) by mx.google.com with ESMTPSA id q3sm7730179wjr.44.2014.11.02.19.08.43 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Sun, 02 Nov 2014 19:08:44 -0800 (PST) Date: Mon, 3 Nov 2014 04:08:41 +0100 From: Mateusz Guzik To: Xin LI Subject: Re: svn commit: r273997 - head/sys/dev/random Message-ID: <20141103030841.GB29497@dft-labs.eu> References: <201411022330.sA2NUpr8004713@svn.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <201411022330.sA2NUpr8004713@svn.freebsd.org> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Nov 2014 03:08:47 -0000 On Sun, Nov 02, 2014 at 11:30:51PM +0000, Xin LI wrote: > Author: delphij > Date: Sun Nov 2 23:30:50 2014 > New Revision: 273997 > URL: https://svnweb.freebsd.org/changeset/base/273997 > > Log: > - Make sure random_adaptor accesses happen only when > random_adaptors_lock is held. > - Use sx_sleep instead of tsleep in read and write path to allow > another thread that registers a new random adapter when waiting. > Assert that random_adaptor is not NULL after reacquiring the lock. > - Capture EINTR/ERESTART from sx_sleep to allow the blocking cycle be > stopped when user requests so, while there also make short > read/write's return 0. > - Move M_WAITOK allocations out of lock scope. > > In collobration with: kib, markm, ian, jilles > Reviewed by: kib, markm > Approved by: so > > Modified: > head/sys/dev/random/random_adaptors.c > > @@ -269,6 +275,8 @@ random_adaptor_read_rate(void) > { > int ret; > > + sx_assert(&random_adaptors_lock, SA_LOCKED); > + > KASSERT(random_adaptor != NULL, ("No active random adaptor in %s", __func__)); > > mtx_lock(&random_read_rate_mtx); This panics with: panic: Lock (sx) random_adaptors not locked @ /usr/src/sys/dev/random/random_adaptors.c:278. cpuid = 0 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe02e7fe4940 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe02e7fe49f0 vpanic() at vpanic+0x189/frame 0xfffffe02e7fe4a70 kassert_panic() at kassert_panic+0x139/frame 0xfffffe02e7fe4ae0 witness_assert() at witness_assert+0x32a/frame 0xfffffe02e7fe4b40 random_adaptor_read_rate() at random_adaptor_read_rate+0x23/frame 0xfffffe02e7fe4b60 live_entropy_sources_feed() at live_entropy_sources_feed+0x2a/frame 0xfffffe02e7fe4b90 Quick look suggests these asserts can be removed since random_read_rate_mtx protects stuff. -- Mateusz Guzik