From owner-svn-src-all@freebsd.org Wed Nov 25 01:08:58 2020 Return-Path: Delivered-To: svn-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 0046846FBEE; Wed, 25 Nov 2020 01:08:57 +0000 (UTC) (envelope-from kevans@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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CgjT56THdz3p4T; Wed, 25 Nov 2020 01:08:57 +0000 (UTC) (envelope-from kevans@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 D135D668; Wed, 25 Nov 2020 01:08:57 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 0AP18vlN096137; Wed, 25 Nov 2020 01:08:57 GMT (envelope-from kevans@FreeBSD.org) Received: (from kevans@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 0AP18vhi096136; Wed, 25 Nov 2020 01:08:57 GMT (envelope-from kevans@FreeBSD.org) Message-Id: <202011250108.0AP18vhi096136@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kevans set sender to kevans@FreeBSD.org using -f From: Kyle Evans Date: Wed, 25 Nov 2020 01:08:57 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r368006 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: kevans X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 368006 X-SVN-Commit-Repository: base 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: 2.1.34 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: Wed, 25 Nov 2020 01:08:58 -0000 Author: kevans Date: Wed Nov 25 01:08:57 2020 New Revision: 368006 URL: https://svnweb.freebsd.org/changeset/base/368006 Log: kern: never restart syscalls calling closefp(), e.g. close(2) All paths leading into closefp() will either replace or remove the fd from the filedesc table, and closefp() will call fo_close methods that can and do currently sleep without regard for the possibility of an ERESTART. This can be dangerous in multithreaded applications as another thread could have opened another file in its place that is subsequently operated on upon restart. The following are seemingly the only ones that will pass back ERESTART in-tree: - sockets (SO_LINGER) - fusefs - nfsclient Reviewed by: jilles, kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D27310 Modified: head/sys/kern/kern_descrip.c Modified: head/sys/kern/kern_descrip.c ============================================================================== --- head/sys/kern/kern_descrip.c Wed Nov 25 00:10:54 2020 (r368005) +++ head/sys/kern/kern_descrip.c Wed Nov 25 01:08:57 2020 (r368006) @@ -1279,6 +1279,15 @@ closefp(struct filedesc *fdp, int fd, struct file *fp, FILEDESC_XUNLOCK(fdp); error = closef(fp, td); + + /* + * All paths leading up to closefp() will have already removed or + * replaced the fd in the filedesc table, so a restart would not + * operate on the same file. + */ + if (error == ERESTART) + error = EINTR; + if (holdleaders) { FILEDESC_XLOCK(fdp); fdp->fd_holdleaderscount--;