From owner-svn-src-head@freebsd.org Thu May 7 13:11:33 2020 Return-Path: Delivered-To: svn-src-head@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 3BAFD2D8B9C; Thu, 7 May 2020 13:11:33 +0000 (UTC) (envelope-from avg@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 49Hv450rtqz49DV; Thu, 7 May 2020 13:11:33 +0000 (UTC) (envelope-from avg@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 18993197BC; Thu, 7 May 2020 13:11:33 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 047DBWPX094462; Thu, 7 May 2020 13:11:32 GMT (envelope-from avg@FreeBSD.org) Received: (from avg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 047DBWqO094461; Thu, 7 May 2020 13:11:32 GMT (envelope-from avg@FreeBSD.org) Message-Id: <202005071311.047DBWqO094461@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org using -f From: Andriy Gapon Date: Thu, 7 May 2020 13:11:32 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r360779 - head/sys/dev/gpio X-SVN-Group: head X-SVN-Commit-Author: avg X-SVN-Commit-Paths: head/sys/dev/gpio X-SVN-Commit-Revision: 360779 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: 2.1.30 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: Thu, 07 May 2020 13:11:33 -0000 Author: avg Date: Thu May 7 13:11:32 2020 New Revision: 360779 URL: https://svnweb.freebsd.org/changeset/base/360779 Log: gpioiic_attach: fix a NULL pointer crash on hints-based systems The attach method uses GPIO_GET_BUS() to get a "newbus" device that provides a pin. But on hints-based systems a GPIO controller driver might not be fully initialized yet and it does not know gpiobus hanging off it. Thus, GPIO_GET_BUS() cannot be called yet. The reason is that controller drivers typically create a child gpiobus using gpiobus_attach_bus() and that leads to the following call chain: gpiobus_attach_bus() -> gpiobus_attach() -> bus_generic_attach(gpiobus) -> gpioiic_attach(). So, gpioiic_attach() is called before gpiobus_attach_bus() returns. I observed this bug with nctgpio driver on amd64. I think that the problem was introduced in r355276. The fix is to avoid calling GPIO_GET_BUS() from the attach method. Instead, we know that on hints-based systems only the parent gpiobus can provide the pins. Nothing is changed for FDT-based systems. MFC after: 1 week Modified: head/sys/dev/gpio/gpioiic.c Modified: head/sys/dev/gpio/gpioiic.c ============================================================================== --- head/sys/dev/gpio/gpioiic.c Thu May 7 12:43:28 2020 (r360778) +++ head/sys/dev/gpio/gpioiic.c Thu May 7 13:11:32 2020 (r360779) @@ -303,10 +303,20 @@ gpioiic_attach(device_t dev) return (ENXIO); } - /* Say what we came up with for pin config. */ + /* + * Say what we came up with for pin config. + * NB: in the !FDT case the controller driver might not be set up enough + * for GPIO_GET_BUS() to work. Also, our parent is the only gpiobus + * that can provide our pins. + */ device_printf(dev, "SCL pin: %s:%d, SDA pin: %s:%d\n", +#ifdef FDT device_get_nameunit(GPIO_GET_BUS(sc->sclpin->dev)), sc->sclpin->pin, device_get_nameunit(GPIO_GET_BUS(sc->sdapin->dev)), sc->sdapin->pin); +#else + device_get_nameunit(device_get_parent(dev)), sc->sclpin->pin, + device_get_nameunit(device_get_parent(dev)), sc->sdapin->pin); +#endif /* Add the bitbang driver as our only child; it will add iicbus. */ device_add_child(sc->dev, "iicbb", -1);