From owner-dev-commits-src-all@freebsd.org Tue Jun 1 23:51:10 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id F0226634760; Tue, 1 Jun 2021 23:51:10 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Fvpp63QXFz53sR; Tue, 1 Jun 2021 23:51:10 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 048FE4E25; Tue, 1 Jun 2021 23:51:10 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 151Np9nd020596; Tue, 1 Jun 2021 23:51:09 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 151Np927020595; Tue, 1 Jun 2021 23:51:09 GMT (envelope-from git) Date: Tue, 1 Jun 2021 23:51:09 GMT Message-Id: <202106012351.151Np927020595@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: 8cd05b883330 - main - amd64: Clear the local TSS when creating a new thread MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 8cd05b883330049d536a40e2f4c9ff92d0e6944e Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Jun 2021 23:51:11 -0000 The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=8cd05b883330049d536a40e2f4c9ff92d0e6944e commit 8cd05b883330049d536a40e2f4c9ff92d0e6944e Author: Mark Johnston AuthorDate: 2021-06-01 23:38:22 +0000 Commit: Mark Johnston CommitDate: 2021-06-01 23:38:22 +0000 amd64: Clear the local TSS when creating a new thread Otherwise it is copied from the creating thread. Then, if either thread exits, the other is left with a dangling pointer, typically resulting in a page fault upon the next context switch. Reported by: syzkaller Reviewed by: kib MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D30607 --- sys/amd64/amd64/vm_machdep.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c index 1acc5dc55c85..7d65269410e0 100644 --- a/sys/amd64/amd64/vm_machdep.c +++ b/sys/amd64/amd64/vm_machdep.c @@ -189,6 +189,8 @@ copy_thread(struct thread *td1, struct thread *td2) * pcb2->pcb_[fg]sbase: cloned above */ + pcb2->pcb_tssp = NULL; + /* Setup to release spin count in fork_exit(). */ td2->td_md.md_spinlock_count = 1; td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;