From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A8762F5328; Tue, 3 Feb 2026 07:55:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770105338; cv=none; b=MUmDJDB1Vf5egHmFFFuFW1viWh0/WyOZ14pPcrK7wzeHp6y1Cnh1W8lhMnpEqPIBpQE0kjj7cT2O0prdTScGlyM70NHOWlkEDTr+ybhjbHjnCOlZeIdVZebyOCESLnEZT7RmFUMeEsvQcT07nfEbgiKQJS/dJOcZ7JRWIGZywds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770105338; c=relaxed/simple; bh=4Vq5HT9GMbuZxPxsT9MI3F5lUAEFdnnd3SV89HgtbiU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HDPNRM+N2DNlVJ6Ec+/Y8iGHHiz5odQ6CLW86RxZ/oPUY83rRjvCOigfCVzhQQMwCS+EBpn2iCR9ymUCS6P8IgzfxvdQHj1fhA2m6MTixpZZWGgENXQPZWlLyVjYvFx+IRnkwNcG1gwfXpF4Q09q+JWSnw9iDaJt3k/FN/RJtuk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZgrHo8ef; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZgrHo8ef" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8E94C116D0; Tue, 3 Feb 2026 07:55:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770105338; bh=4Vq5HT9GMbuZxPxsT9MI3F5lUAEFdnnd3SV89HgtbiU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZgrHo8efwWhKG72A/lo1uIpJEsxbnmB/+X4lxJ1ROODvZ7p/Um6aznZHdBfWooFEj vLjRO79jepU/n+6Ls4isDYUW1zpcPed4CEUeDDk6iIz9gUlw3UmT/pMPQC9gXYAzjL KsDavt5Wjby1NsZgD9GTkXSJbNj56etLNZj1l8ewMWXcDImInn0lLkbvhkL4dxlHH5 5/H3446d2K1NERiVeR5hAveV1iUVLKRUeWQ3Sbsg/ve++lnksJ3NLQb/yU8E3gEfu3 OfbRhveeTSAzsy8G4kE18sWYTT9oVndeNLptmGzbk7IGqKWuwbzx2HS4IkkLgruy8W ZriSncHdyX6ww== Date: Tue, 3 Feb 2026 15:55:33 +0800 From: "Peter Chen (CIX)" To: "Thomas Richard (TI)" Cc: Pawel Laszczak , Roger Quadros , Greg Kroah-Hartman , theo.lebrun@bootlin.com, Frank Li , Thomas Petazzoni , Gregory CLEMENT , richard.genoud@bootlin.com, Udit Kumar , Prasanth Mantena , Abhash Kumar , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Chen , stable@vger.kernel.org Subject: Re: [PATCH] usb: cdns3: fix role switching during resume Message-ID: <20260203075533.GA326240@nchen-desktop> References: <20260130-usb-cdns3-fix-role-switching-during-resume-v1-1-44c456852b52@bootlin.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260130-usb-cdns3-fix-role-switching-during-resume-v1-1-44c456852b52@bootlin.com> On 26-01-30 11:05:45, Thomas Richard (TI) wrote: > If the role change while we are suspended, the cdns3 driver switches to the > new mode during resume. However, switching to host mode in this context > causes a NULL pointer dereference. > > The host role's start() operation registers a xhci-hcd device, but its > probe is deferred while we are in the resume path. The host role's resume() > operation assumes the xhci-hcd device is already probed, which is not the > case, leading to the dereference. Since the start() operation of the new > role is already called, the resume operation can be skipped. > > So skip the resume operation for the new role if a role switch occurs > during resume. Once the resume sequence is complete, the xhci-hcd device > can be probed in case of host mode. > > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000208 > Mem abort info: > ... > Data abort info: > ... > [0000000000000208] pgd=0000000000000000, p4d=0000000000000000 > Internal error: Oops: 0000000096000004 [#1] SMP > Modules linked in: > CPU: 0 UID: 0 PID: 146 Comm: sh Not tainted > 6.19.0-rc7-00013-g6e64f4aabfae-dirty #135 PREEMPT > Hardware name: Texas Instruments J7200 EVM (DT) > pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : usb_hcd_is_primary_hcd+0x0/0x1c > lr : cdns_host_resume+0x24/0x5c > ... > Call trace: > usb_hcd_is_primary_hcd+0x0/0x1c (P) > cdns_resume+0x6c/0xbc > cdns3_controller_resume.isra.0+0xe8/0x17c > cdns3_plat_resume+0x18/0x24 > platform_pm_resume+0x2c/0x68 > dpm_run_callback+0x90/0x248 > device_resume+0x100/0x24c > dpm_resume+0x190/0x2ec > dpm_resume_end+0x18/0x34 > suspend_devices_and_enter+0x2b0/0xa44 > pm_suspend+0x16c/0x5fc > state_store+0x80/0xec > kobj_attr_store+0x18/0x2c > sysfs_kf_write+0x7c/0x94 > kernfs_fop_write_iter+0x130/0x1dc > vfs_write+0x240/0x370 > ksys_write+0x70/0x108 > __arm64_sys_write+0x1c/0x28 > invoke_syscall+0x48/0x10c > el0_svc_common.constprop.0+0x40/0xe0 > do_el0_svc+0x1c/0x28 > el0_svc+0x34/0x108 > el0t_64_sync_handler+0xa0/0xe4 > el0t_64_sync+0x198/0x19c > Code: 52800003 f9407ca5 d63f00a0 17ffffe4 (f9410401) > ---[ end trace 0000000000000000 ]--- > > Cc: stable@vger.kernel.org > Fixes: 2cf2581cd229 ("usb: cdns3: add power lost support for system resume") > Signed-off-by: Thomas Richard (TI) Acked-by: Peter Chen Peter > --- > This patch is related to the following discussion: > https://lore.kernel.org/all/8743fec1-301d-46e1-89bf-7952c73faa86@bootlin.com/ > --- > drivers/usb/cdns3/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c > index 1243a5cea91b..f0e32227c0b7 100644 > --- a/drivers/usb/cdns3/core.c > +++ b/drivers/usb/cdns3/core.c > @@ -551,7 +551,7 @@ int cdns_resume(struct cdns *cdns) > } > } > > - if (cdns->roles[cdns->role]->resume) > + if (!role_changed && cdns->roles[cdns->role]->resume) > cdns->roles[cdns->role]->resume(cdns, power_lost); > > return 0; > -- Best regards, Peter