Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752611AbbK1Qe4 (ORCPT ); Sat, 28 Nov 2015 11:34:56 -0500 Received: from mga01.intel.com ([192.55.52.88]:22621 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752472AbbK1Qeu (ORCPT ); Sat, 28 Nov 2015 11:34:50 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,357,1444719600"; d="scan'208";a="608884695" Date: Sat, 28 Nov 2015 18:34:47 +0200 From: Jarkko Sakkinen To: martin.wilck@ts.fujitsu.com Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, u.kleine-koenig@pengutronix.de Subject: Re: [tpmdd-devel] [PATCH] base/platform: fix panic when probe function is NULL Message-ID: <20151128163447.GD6518@intel.com> References: <1448564494-23218-1-git-send-email-martin.wilck@ts.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448564494-23218-1-git-send-email-martin.wilck@ts.fujitsu.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2401 Lines: 66 On Thu, Nov 26, 2015 at 08:01:34PM +0100, martin.wilck@ts.fujitsu.com wrote: > From: Martin Wilck > > Since b8b2c7d845d5, platform_drv_probe() is called for all platform > devices. If drv->probe is NULL, and dev_pm_domain_attach() fails, > platform_drv_probe() will return the error code from dev_pm_domain_attach(). > > This causes real_probe() to enter the "probe_failed" path and set > dev->driver to NULL. Before b8b2c7d845d5, real_probe() would assume > success if both dev->bus->probe and drv->probe are missing. > > This may cause a panic later. For example, inserting the tpm_tis > driver with parameter "force=1" (i.e. registering tpm_tis as a platform > driver) will panic in tpmm_chip_alloc() because dev->driver is NULL: > > chip->cdev.owner = chip->pdev->driver->owner; > > This patch fixes this by returning success in platform_drv_probe() if > "just" dev_pm_domain_attach() had failed. This restores the semantics > of platform_device_register_XXX() if the associated platform driver has > no "probe" function. > > Fixes: b8b2c7d845d5 ("base/platform: assert that dev_pm_domain > callbacks are called unconditionally") > > Signed-off-by: Martin Wilck Acked-by: Jarkko Sakkinen > --- > drivers/base/platform.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 1dd6d3b..c994e76 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -513,10 +513,14 @@ static int platform_drv_probe(struct device *_dev) > return ret; > > ret = dev_pm_domain_attach(_dev, true); > - if (ret != -EPROBE_DEFER && drv->probe) { > - ret = drv->probe(dev); > - if (ret) > - dev_pm_domain_detach(_dev, true); > + if (ret != -EPROBE_DEFER) { > + if (drv->probe) { > + ret = drv->probe(dev); > + if (ret) > + dev_pm_domain_detach(_dev, true); > + } else > + /* don't fail if just dev_pm_domain_attach failed */ > + ret = 0; > } > > if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { > -- > 1.8.3.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/