From owner-freebsd-stable@FreeBSD.ORG Wed Aug 24 20:04:46 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 434EA1065673 for ; Wed, 24 Aug 2011 20:04:46 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) by mx1.freebsd.org (Postfix) with ESMTP id F25888FC16 for ; Wed, 24 Aug 2011 20:04:45 +0000 (UTC) Received: from slw by zxy.spb.ru with local (Exim 4.69 (FreeBSD)) (envelope-from ) id 1QwJh2-000Jbp-Mh; Thu, 25 Aug 2011 00:04:56 +0400 Date: Thu, 25 Aug 2011 00:04:56 +0400 From: Slawa Olhovchenkov To: Kostik Belousov Message-ID: <20110824200456.GE48394@zxy.spb.ru> References: <20110824181907.GA48394@zxy.spb.ru> <20110824190703.GY17489@deviant.kiev.zoral.com.ua> <20110824192446.GB48394@zxy.spb.ru> <20110824193202.GZ17489@deviant.kiev.zoral.com.ua> <20110824194229.GC48394@zxy.spb.ru> <20110824195035.GA17489@deviant.kiev.zoral.com.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110824195035.GA17489@deviant.kiev.zoral.com.ua> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false Cc: freebsd-stable@freebsd.org Subject: Re: sigwait return 4 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Aug 2011 20:04:46 -0000 On Wed, Aug 24, 2011 at 10:50:35PM +0300, Kostik Belousov wrote: > On Wed, Aug 24, 2011 at 11:42:29PM +0400, Slawa Olhovchenkov wrote: > > On Wed, Aug 24, 2011 at 10:32:02PM +0300, Kostik Belousov wrote: > > > > > > > What should the system do for a delivered signal not present in the set ? > > > > > I guess this is the case of your ktrace. > > > > > > > > > > Looking at the SUSv4, I see no mention of the situation, but in Oracle > > > > > SunOS 5.10 man page for sigwait(2), it is said explicitely > > > > > EINTR The wait was interrupted by an unblocked, caught signal. > > > > > > > > I don't think you right in this case. > > > > This is kas-milter and in this thread (this is multi-thread > > > > application) kas-milter wait for USR2 for reload config. > > > > > > > > System return from sigwait only on USR2, but not each return w/ > > > > non-zero return code. > > > > > > > > On freebsd7 this application don't complain about sigwait's return value. > > > > > > Could it be that some other thread has the signal unblocked ? > > > (You can verify this with procstat -j). > > > > > > Can you write the self-contained test case that demonstrates the behaviour ? > > > > This is closed-source software. > How is this statement related to the creation of the standalone test case ? I don't know what testing. > > # procstat -j > > PID TID COMM SIG FLAGS > > 1395 100199 kas-milter USR2 -- > > 1395 100232 kas-milter USR2 -- > > Both threads have the signal not blocked. This is not definitive, > since signal must be blocked during the call to sigwait(2). Note that > the SUSv4 says that "The signals defined by set shall have been > blocked at the time of the call to sigwait(); otherwise, the behavior is > undefined." This is not suitable to return '4'. And where root of this '4'? In /sys/kern/kern_sig.c:sigwait we call error = kern_sigtimedwait(td, set, &ksi, NULL); --- no timeout.