From owner-svn-src-head@freebsd.org Tue Oct 31 11:51:36 2017 Return-Path: Delivered-To: svn-src-head@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 01617E56EB5; Tue, 31 Oct 2017 11:51:36 +0000 (UTC) (envelope-from tijl@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 C2D97718AA; Tue, 31 Oct 2017 11:51:35 +0000 (UTC) (envelope-from tijl@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v9VBpYND040547; Tue, 31 Oct 2017 11:51:34 GMT (envelope-from tijl@FreeBSD.org) Received: (from tijl@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v9VBpYI1040545; Tue, 31 Oct 2017 11:51:34 GMT (envelope-from tijl@FreeBSD.org) Message-Id: <201710311151.v9VBpYI1040545@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: tijl set sender to tijl@FreeBSD.org using -f From: Tijl Coosemans Date: Tue, 31 Oct 2017 11:51:34 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r325232 - in head/sys: amd64/amd64 i386/i386 X-SVN-Group: head X-SVN-Commit-Author: tijl X-SVN-Commit-Paths: in head/sys: amd64/amd64 i386/i386 X-SVN-Commit-Revision: 325232 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: 2.1.23 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: Tue, 31 Oct 2017 11:51:36 -0000 Author: tijl Date: Tue Oct 31 11:51:34 2017 New Revision: 325232 URL: https://svnweb.freebsd.org/changeset/base/325232 Log: Set the return address for stack entry points to zero. Stack unwinders treat zero as a stop condition. The value on the stack can be non-zero because thread stacks may be arbitrary memory provided via pthread_attr_setstack(3) or may be recycled from previous threads. Reference: https://lists.freebsd.org/pipermail/freebsd-current/2017-August/066855.html https://lists.freebsd.org/pipermail/freebsd-current/2017-October/067254.html Discussed with: kib MFC after: 1 week Modified: head/sys/amd64/amd64/vm_machdep.c head/sys/i386/i386/vm_machdep.c Modified: head/sys/amd64/amd64/vm_machdep.c ============================================================================== --- head/sys/amd64/amd64/vm_machdep.c Tue Oct 31 11:29:16 2017 (r325231) +++ head/sys/amd64/amd64/vm_machdep.c Tue Oct 31 11:51:34 2017 (r325232) @@ -508,6 +508,9 @@ cpu_set_upcall(struct thread *td, void (*entry)(void * (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; td->td_frame->tf_rip = (uintptr_t)entry; + /* Return address sentinel value to stop stack unwinding. */ + suword32((void *)td->td_frame->tf_rsp, 0); + /* Pass the argument to the entry point. */ suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), (uint32_t)(uintptr_t)arg); @@ -530,6 +533,9 @@ cpu_set_upcall(struct thread *td, void (*entry)(void * td->td_frame->tf_fs = _ufssel; td->td_frame->tf_gs = _ugssel; td->td_frame->tf_flags = TF_HASSEGS; + + /* Return address sentinel value to stop stack unwinding. */ + suword((void *)td->td_frame->tf_rsp, 0); /* Pass the argument to the entry point. */ td->td_frame->tf_rdi = (register_t)arg; Modified: head/sys/i386/i386/vm_machdep.c ============================================================================== --- head/sys/i386/i386/vm_machdep.c Tue Oct 31 11:29:16 2017 (r325231) +++ head/sys/i386/i386/vm_machdep.c Tue Oct 31 11:51:34 2017 (r325232) @@ -524,6 +524,9 @@ cpu_set_upcall(struct thread *td, void (*entry)(void * (((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; td->td_frame->tf_eip = (int)entry; + /* Return address sentinel value to stop stack unwinding. */ + suword((void *)td->td_frame->tf_esp, 0); + /* Pass the argument to the entry point. */ suword((void *)(td->td_frame->tf_esp + sizeof(void *)), (int)arg);