Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934244AbcKILLJ (ORCPT ); Wed, 9 Nov 2016 06:11:09 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55560 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934226AbcKILLE (ORCPT ); Wed, 9 Nov 2016 06:11:04 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Laurent Pinchart , Tony Lindgren , Bin Liu Subject: [PATCH 4.8 130/138] usb: musb: Fix hardirq-safe hardirq-unsafe lock order error Date: Wed, 9 Nov 2016 11:46:53 +0100 Message-Id: <20161109102850.941575451@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161109102844.808685475@linuxfoundation.org> References: <20161109102844.808685475@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3116 Lines: 87 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tony Lindgren commit d8e5f0eca1e88215e45aca27115ea747e6164da1 upstream. If we configure musb with 2430 glue as a peripheral, and then rmmod omap2430 module, we'll get the following error: [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] ... rmmod/413 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (&phy->mutex){+.+.+.}, at: [] phy_power_off+0x1c/0xb8 [ 204.678710] and this task is already holding: (&(&musb->lock)->rlock){-.-...}, at: [] musb_gadget_stop+0x24/0xec [musb_hdrc] which would create a new lock dependency: (&(&musb->lock)->rlock){-.-...} -> (&phy->mutex){+.+.+.} ... This is because some glue layers expect musb_platform_enable/disable to be called with spinlock held, and 2430 glue layer has USB PHY on the I2C bus using a mutex. We could fix the glue layers to take the spinlock, but we still have a problem of musb_plaform_enable/disable being called in an unbalanced manner. So that would still lead into USB PHY enable/disable related problems for omap2430 glue layer. While it makes sense to only enable USB PHY when needed from PM point of view, in this case we just can't do it yet without breaking things. So let's just revert phy_enable/disable related changes instead and reconsider this after we have fixed musb_platform_enable/disable to be balanced. Fixes: a83e17d0f73b ("usb: musb: Improve PM runtime and phy handling for 2430 glue layer") Reviewed-by: Laurent Pinchart Signed-off-by: Tony Lindgren Signed-off-by: Bin Liu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/omap2430.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- a/drivers/usb/musb/omap2430.c +++ b/drivers/usb/musb/omap2430.c @@ -337,6 +337,7 @@ static int omap2430_musb_init(struct mus } musb->isr = omap2430_musb_interrupt; phy_init(musb->phy); + phy_power_on(musb->phy); l = musb_readl(musb->mregs, OTG_INTERFSEL); @@ -373,8 +374,6 @@ static void omap2430_musb_enable(struct struct musb_hdrc_platform_data *pdata = dev_get_platdata(dev); struct omap_musb_board_data *data = pdata->board_data; - if (!WARN_ON(!musb->phy)) - phy_power_on(musb->phy); omap2430_set_power(musb, true, glue->cable_connected); @@ -413,9 +412,6 @@ static void omap2430_musb_disable(struct struct device *dev = musb->controller; struct omap2430_glue *glue = dev_get_drvdata(dev->parent); - if (!WARN_ON(!musb->phy)) - phy_power_off(musb->phy); - if (glue->status != MUSB_UNKNOWN) omap_control_usb_set_mode(glue->control_otghs, USB_MODE_DISCONNECT); @@ -429,6 +425,7 @@ static int omap2430_musb_exit(struct mus struct omap2430_glue *glue = dev_get_drvdata(dev->parent); omap2430_low_level_exit(musb); + phy_power_off(musb->phy); phy_exit(musb->phy); musb->phy = NULL; cancel_work_sync(&glue->omap_musb_mailbox_work);