From owner-svn-src-head@freebsd.org Thu Mar 22 15:34:38 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EF7D8F4F117; Thu, 22 Mar 2018 15:34:37 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A0B137B492; Thu, 22 Mar 2018 15:34:37 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 9AE83132FD; Thu, 22 Mar 2018 15:34:37 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w2MFYbxe047215; Thu, 22 Mar 2018 15:34:37 GMT (envelope-from imp@FreeBSD.org) Received: (from imp@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w2MFYbC8047214; Thu, 22 Mar 2018 15:34:37 GMT (envelope-from imp@FreeBSD.org) Message-Id: <201803221534.w2MFYbC8047214@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: imp set sender to imp@FreeBSD.org using -f From: Warner Losh Date: Thu, 22 Mar 2018 15:34:37 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r331362 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: imp X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 331362 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 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: Thu, 22 Mar 2018 15:34:38 -0000 Author: imp Date: Thu Mar 22 15:34:37 2018 New Revision: 331362 URL: https://svnweb.freebsd.org/changeset/base/331362 Log: Drop any recursed taking of Giant once and for all at the top of kern_reboot(). The shutdown path is now safe to run without Giant. Discussed with: kib@ Sponsored by: Netflix Modified: head/sys/kern/kern_shutdown.c Modified: head/sys/kern/kern_shutdown.c ============================================================================== --- head/sys/kern/kern_shutdown.c Thu Mar 22 15:32:57 2018 (r331361) +++ head/sys/kern/kern_shutdown.c Thu Mar 22 15:34:37 2018 (r331362) @@ -366,6 +366,17 @@ kern_reboot(int howto) { static int once = 0; + /* + * Normal paths here don't hold Giant, but we can wind up here + * unexpectedly with it held. Drop it now so we don't have to + * drop and pick it up elsewhere. The paths it is locking will + * never be returned to, and it is preferable to preclude + * deadlock than to lock against code that won't ever + * continue. + */ + while (mtx_owned(&Giant)) + mtx_unlock(&Giant); + #if defined(SMP) /* * Bind us to the first CPU so that all shutdown code runs there. Some