From owner-svn-src-all@freebsd.org Mon Feb 8 23:11:24 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EA7CAAA0169; Mon, 8 Feb 2016 23:11:24 +0000 (UTC) (envelope-from jhb@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 mx1.freebsd.org (Postfix) with ESMTPS id B8AE71F68; Mon, 8 Feb 2016 23:11:24 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u18NBN1Z074130; Mon, 8 Feb 2016 23:11:23 GMT (envelope-from jhb@FreeBSD.org) Received: (from jhb@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u18NBNXr074129; Mon, 8 Feb 2016 23:11:23 GMT (envelope-from jhb@FreeBSD.org) Message-Id: <201602082311.u18NBNXr074129@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: jhb set sender to jhb@FreeBSD.org using -f From: John Baldwin Date: Mon, 8 Feb 2016 23:11:23 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r295419 - head/sys/kern X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 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: Mon, 08 Feb 2016 23:11:25 -0000 Author: jhb Date: Mon Feb 8 23:11:23 2016 New Revision: 295419 URL: https://svnweb.freebsd.org/changeset/base/295419 Log: Call kthread_exit() rather than kproc_exit() for a premature kthread exit. Kernel threads (and processes) are supposed to call kthread_exit() (or kproc_exit()) to terminate. However, the kernel includes a fallback in fork_exit() to force a kthread exit if a kernel thread's "main" routine returns. This fallback was added back when the kernel only had processes and was not updated to call kthread_exit() instead of kproc_exit() when threads were added to the kernel. This mistake was particular exciting when the errant thread belonged to proc0. Due to the missing P_KTHREAD flag the fallback did not kick in and instead tried to return to userland via whatever garbage was in the trapframe. With P_KTHREAD set it tried to terminate proc0 resulting in other amusements. PR: 204999 MFC after: 1 week Modified: head/sys/kern/kern_fork.c Modified: head/sys/kern/kern_fork.c ============================================================================== --- head/sys/kern/kern_fork.c Mon Feb 8 23:06:27 2016 (r295418) +++ head/sys/kern/kern_fork.c Mon Feb 8 23:11:23 2016 (r295419) @@ -1040,7 +1040,7 @@ fork_exit(void (*callout)(void *, struct if (p->p_flag & P_KTHREAD) { printf("Kernel thread \"%s\" (pid %d) exited prematurely.\n", td->td_name, p->p_pid); - kproc_exit(0); + kthread_exit(); } mtx_assert(&Giant, MA_NOTOWNED);