From owner-svn-src-all@freebsd.org Fri Mar 1 01:18:40 2019 Return-Path: Delivered-To: svn-src-all@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 9DDA41521579; Fri, 1 Mar 2019 01:18:40 +0000 (UTC) (envelope-from mw@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) server-signature RSA-PSS (4096 bits) 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 3F7DF6C1C3; Fri, 1 Mar 2019 01:18:40 +0000 (UTC) (envelope-from mw@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 30A84D627; Fri, 1 Mar 2019 01:18:40 +0000 (UTC) (envelope-from mw@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x211Iegw027671; Fri, 1 Mar 2019 01:18:40 GMT (envelope-from mw@FreeBSD.org) Received: (from mw@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x211IeVj027670; Fri, 1 Mar 2019 01:18:40 GMT (envelope-from mw@FreeBSD.org) Message-Id: <201903010118.x211IeVj027670@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mw set sender to mw@FreeBSD.org using -f From: Marcin Wojtas Date: Fri, 1 Mar 2019 01:18:40 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r344676 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mw X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 344676 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 3F7DF6C1C3 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.95 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_SHORT(-0.95)[-0.948,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 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: Fri, 01 Mar 2019 01:18:40 -0000 Author: mw Date: Fri Mar 1 01:18:39 2019 New Revision: 344676 URL: https://svnweb.freebsd.org/changeset/base/344676 Log: Prevent detaching driver if the attach is not finished When the device is in attaching state, detach should return EBUSY instead of success. In other case, there could be race between attach and detach during the driver unloading. If driver goes sleep and releases GIANT lock during attaching, unloading module could start. In such case when attach continues after module unload, page fault "supervisor read instruction, page not present" occurred. This patch works around the real issue, which is a locking deficiency of the busses. Submitted by: Rafal Kozik Reviewed by: imp Obtained from: Semihalf MFC after: 2 weeks Sponsored by: Amazon, Inc. Differential Revision: https://reviews.freebsd.org/D19375 Modified: head/sys/kern/subr_bus.c Modified: head/sys/kern/subr_bus.c ============================================================================== --- head/sys/kern/subr_bus.c Thu Feb 28 23:00:47 2019 (r344675) +++ head/sys/kern/subr_bus.c Fri Mar 1 01:18:39 2019 (r344676) @@ -3004,6 +3004,10 @@ device_detach(device_t dev) PDEBUG(("%s", DEVICENAME(dev))); if (dev->state == DS_BUSY) return (EBUSY); + if (dev->state == DS_ATTACHING) { + device_printf(dev, "device in attaching state! Deferring detach.\n"); + return (EBUSY); + } if (dev->state != DS_ATTACHED) return (0);