From owner-svn-src-all@FreeBSD.ORG Thu Jan 7 00:47:50 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A4F02106566B; Thu, 7 Jan 2010 00:47:50 +0000 (UTC) (envelope-from attilio@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 7AD9D8FC08; Thu, 7 Jan 2010 00:47:50 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o070lok9091016; Thu, 7 Jan 2010 00:47:50 GMT (envelope-from attilio@svn.freebsd.org) Received: (from attilio@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o070looW091014; Thu, 7 Jan 2010 00:47:50 GMT (envelope-from attilio@svn.freebsd.org) Message-Id: <201001070047.o070looW091014@svn.freebsd.org> From: Attilio Rao Date: Thu, 7 Jan 2010 00:47:50 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r201703 - head/sys/kern X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 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: Thu, 07 Jan 2010 00:47:50 -0000 Author: attilio Date: Thu Jan 7 00:47:50 2010 New Revision: 201703 URL: http://svn.freebsd.org/changeset/base/201703 Log: Exclusive waiters sleeping with LK_SLEEPFAIL on and using interruptible sleeps/timeout may have left spourious lk_exslpfail counts on, so clean it up even when accessing a shared queue acquisition, giving to lk_exslpfail the value of 'upper limit'. In the worst case scenario, infact (mixed interruptible sleep / LK_SLEEPFAIL waiters) what may happen is that both queues are awaken even if that's not necessary, but still no harm. Reported by: Lucius Windschuh Reviewed by: kib Tested by: pho, Lucius Windschuh Modified: head/sys/kern/kern_lock.c Modified: head/sys/kern/kern_lock.c ============================================================================== --- head/sys/kern/kern_lock.c Thu Jan 7 00:44:54 2010 (r201702) +++ head/sys/kern/kern_lock.c Thu Jan 7 00:47:50 2010 (r201703) @@ -300,7 +300,14 @@ wakeupshlk(struct lock *lk, const char * } } else { - MPASS(lk->lk_exslpfail == 0); + + /* + * Exclusive waiters sleeping with LK_SLEEPFAIL on + * and using interruptible sleeps/timeout may have + * left spourious lk_exslpfail counts on, so clean + * it up anyway. + */ + lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; } @@ -959,7 +966,14 @@ __lockmgr_args(struct lock *lk, u_int fl queue = SQ_SHARED_QUEUE; } } else { - MPASS(lk->lk_exslpfail == 0); + + /* + * Exclusive waiters sleeping with LK_SLEEPFAIL + * on and using interruptible sleeps/timeout + * may have left spourious lk_exslpfail counts + * on, so clean it up anyway. + */ + lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; } @@ -1037,8 +1051,16 @@ __lockmgr_args(struct lock *lk, u_int fl queue = SQ_EXCLUSIVE_QUEUE; v &= ~LK_EXCLUSIVE_WAITERS; } else { + + /* + * Exclusive waiters sleeping with + * LK_SLEEPFAIL on and using + * interruptible sleeps/timeout may + * have left spourious lk_exslpfail + * counts on, so clean it up anyway. + */ MPASS(v & LK_SHARED_WAITERS); - MPASS(lk->lk_exslpfail == 0); + lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; v &= ~LK_SHARED_WAITERS; }