From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B798AC2D0A3 for ; Thu, 29 Oct 2020 13:06:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CA4820732 for ; Thu, 29 Oct 2020 13:06:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725964AbgJ2NGi (ORCPT ); Thu, 29 Oct 2020 09:06:38 -0400 Received: from mga04.intel.com ([192.55.52.120]:44850 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbgJ2NGi (ORCPT ); Thu, 29 Oct 2020 09:06:38 -0400 IronPort-SDR: GZBPg7XHoF2ZxwcC5RmsniUVYZ2HtZ45Vv/dAL3eFgK988VqG7IVHXcGRfCNi8qzStisepNE2T /HsmTC2w+FaA== X-IronPort-AV: E=McAfee;i="6000,8403,9788"; a="165842568" X-IronPort-AV: E=Sophos;i="5.77,430,1596524400"; d="scan'208";a="165842568" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2020 06:06:38 -0700 IronPort-SDR: bPeCk+16lu5x5zLw+OhOSYjZhOdaE5kCA2LzaOoxHU4d7V4iG2mNnWY6kj1GkE2U4jGD+WuS2S ikK+3/mrh9dQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,430,1596524400"; d="scan'208";a="351438187" Received: from mattu-haswell.fi.intel.com (HELO [10.237.72.170]) ([10.237.72.170]) by fmsmga004.fm.intel.com with ESMTP; 29 Oct 2020 06:06:36 -0700 Subject: Re: [PATCH 3/3] xhci: Don't create stream debugfs files with spinlock held. To: Sebastian Andrzej Siewior Cc: Mike Galbraith , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, Hans de Goede , Li Jun References: <20201028203124.375344-1-mathias.nyman@linux.intel.com> <20201028203124.375344-4-mathias.nyman@linux.intel.com> <1cbb8b7defb1db1d4747995c11ebebb3dd9a66ec.camel@gmx.de> <30dd5079-375d-a2a3-cab3-1b2740661ea8@linux.intel.com> <20201029113805.tdsissnjq4acemle@linutronix.de> From: Mathias Nyman Autocrypt: addr=mathias.nyman@linux.intel.com; prefer-encrypt=mutual; keydata= mQINBFMB0ccBEADd+nZnZrFDsIjQtclVz6OsqFOQ6k0nQdveiDNeBuwyFYykkBpaGekoHZ6f lH4ogPZzQ+pzoJEMlRGXc881BIggKMCMH86fYJGfZKWdfpg9O6mqSxyEuvBHKe9eZCBKPvoC L2iwygtO8TcXXSCynvXSeZrOwqAlwnxWNRm4J2ikDck5S5R+Qie0ZLJIfaId1hELofWfuhy+ tOK0plFR0HgVVp8O7zWYT2ewNcgAzQrRbzidA3LNRfkL7jrzyAxDapuejuK8TMrFQT/wW53e uegnXcRJaibJD84RUJt+mJrn5BvZ0MYfyDSc1yHVO+aZcpNr+71yZBQVgVEI/AuEQ0+p9wpt O9Wt4zO2KT/R5lq2lSz1MYMJrtfFRKkqC6PsDSB4lGSgl91XbibK5poxrIouVO2g9Jabg04T MIPpVUlPme3mkYHLZUsboemRQp5/pxV4HTFR0xNBCmsidBICHOYAepCzNmfLhfo1EW2Uf+t4 L8IowAaoURKdgcR2ydUXjhACVEA/Ldtp3ftF4hTQ46Qhba/p4MUFtDAQ5yeA5vQVuspiwsqB BoL/298+V119JzM998d70Z1clqTc8fiGMXyVnFv92QKShDKyXpiisQn2rrJVWeXEIVoldh6+ J8M3vTwzetnvIKpoQdSFJ2qxOdQ8iYRtz36WYl7hhT3/hwkHuQARAQABtCdNYXRoaWFzIE55 bWFuIDxtYXRoaWFzLm55bWFuQGdtYWlsLmNvbT6JAjsEEwECACUCGwMGCwkIBwMCBhUIAgkK CwQWAgMBAh4BAheABQJTAeo1AhkBAAoJEFiDn/uYk8VJOdIP/jhA+RpIZ7rdUHFIYkHEKzHw tkwrJczGA5TyLgQaI8YTCTPSvdNHU9Rj19mkjhUO/9MKvwfoT2RFYqhkrtk0K92STDaBNXTL JIi4IHBqjXOyJ/dPADU0xiRVtCHWkBgjEgR7Wihr7McSdVpgupsaXhbZjXXgtR/N7PE0Wltz hAL2GAnMuIeJyXhIdIMLb+uyoydPCzKdH6znfu6Ox76XfGWBCqLBbvqPXvk4oH03jcdt+8UG 2nfSeti/To9ANRZIlSKGjddCGMa3xzjtTx9ryf1Xr0MnY5PeyNLexpgHp93sc1BKxKKtYaT0 lR6p0QEKeaZ70623oB7Sa2Ts4IytqUVxkQKRkJVWeQiPJ/dZYTK5uo15GaVwufuF8VTwnMkC 4l5X+NUYNAH1U1bpRtlT40aoLEUhWKAyVdowxW4yGCP3nL5E69tZQQgsag+OnxBa6f88j63u wxmOJGNXcwCerkCb+wUPwJzChSifFYmuV5l89LKHgSbv0WHSN9OLkuhJO+I9fsCNvro1Y7dT U/yq4aSVzjaqPT3yrnQkzVDxrYT54FLWO1ssFKAOlcfeWzqrT9QNcHIzHMQYf5c03Kyq3yMI Xi91hkw2uc/GuA2CZ8dUD3BZhUT1dm0igE9NViE1M7F5lHQONEr7MOCg1hcrkngY62V6vh0f RcDeV0ISwlZWuQINBFMB0ccBEACXKmWvojkaG+kh/yipMmqZTrCozsLeGitxJzo5hq9ev31N 2XpPGx4AGhpccbco63SygpVN2bOd0W62fJJoxGohtf/g0uVtRSuK43OTstoBPqyY/35+VnAV oA5cnfvtdx5kQPIL6LRcxmYKgN4/3+A7ejIxbOrjWFmbWCC+SgX6mzHHBrV0OMki8R+NnrNa NkUmMmosi7jBSKdoi9VqDqgQTJF/GftvmaZHqgmVJDWNrCv7UiorhesfIWPt1O/AIk9luxlE dHwkx5zkWa9CGYvV6LfP9BznendEoO3qYZ9IcUlW727Le80Q1oh69QnHoI8pODDBBTJvEq1h bOWcPm/DsNmDD8Rwr/msRmRyIoxjasFi5WkM/K/pzujICKeUcNGNsDsEDJC5TCmRO/TlvCvm 0X+vdfEJRZV6Z+QFBflK1asUz9QHFre5csG8MyVZkwTR9yUiKi3KiqQdaEu+LuDD2CGF5t68 xEl66Y6mwfyiISkkm3ETA4E8rVZP1rZQBBm83c5kJEDvs0A4zrhKIPTcI1smK+TWbyVyrZ/a mGYDrZzpF2N8DfuNSqOQkLHIOL3vuOyx3HPzS05lY3p+IIVmnPOEdZhMsNDIGmVorFyRWa4K uYjBP/W3E5p9e6TvDSDzqhLoY1RHfAIadM3I8kEx5wqco67VIgbIHHB9DbRcxQARAQABiQIf BBgBAgAJBQJTAdHHAhsMAAoJEFiDn/uYk8VJb7AQAK56tgX8V1Wa6RmZDmZ8dmBC7W8nsMRz PcKWiDSMIvTJT5bygMy1lf7gbHXm7fqezRtSfXAXr/OJqSA8LB2LWfThLyuuCvrdNsQNrI+3 D+hjHJjhW/4185y3EdmwwHcelixPg0X9EF+lHCltV/w29Pv3PiGDkoKxJrnOpnU6jrwiBebz eAYBfpSEvrCm4CR4hf+T6MdCs64UzZnNt0nxL8mLCCAGmq1iks9M4bZk+LG36QjCKGh8PDXz 9OsnJmCggptClgjTa7pO6040OW76pcVrP2rZrkjo/Ld/gvSc7yMO/m9sIYxLIsR2NDxMNpmE q/H7WO+2bRG0vMmsndxpEYS4WnuhKutoTA/goBEhtHu1fg5KC+WYXp9wZyTfeNPrL0L8F3N1 BCEYefp2JSZ/a355X6r2ROGSRgIIeYjAiSMgGAZMPEVsdvKsYw6BH17hDRzltNyIj5S0dIhb Gjynb3sXforM/GVbr4mnuxTdLXQYlj2EJ4O4f0tkLlADT7podzKSlSuZsLi2D+ohKxtP3U/r 42i8PBnX2oAV0UIkYk7Oel/3hr0+BP666SnTls9RJuoXc7R5XQVsomqXID6GmjwFQR5Wh/RE IJtkiDAsk37cfZ9d1kZ2gCQryTV9lmflSOB6AFZkOLuEVSC5qW8M/s6IGDfYXN12YJaZPptJ fiD/ Message-ID: <29cf8ca3-0fe7-da51-c8ae-ad5c67af4dde@linux.intel.com> Date: Thu, 29 Oct 2020 15:08:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201029113805.tdsissnjq4acemle@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 29.10.2020 13.38, Sebastian Andrzej Siewior wrote: > On 2020-10-29 13:22:20 [+0200], Mathias Nyman wrote: >> On 29.10.2020 13.11, Mike Galbraith wrote: >>> On Thu, 2020-10-29 at 11:41 +0200, Mathias Nyman wrote: >>>> Can you check if this can be reproduced with 5.9 kernel? >>> >>> Nope, 5.9.2 didn't reproduce. >>> >> >> Very odd. >> It might be hard to reproduce as it requires xhci ring expansion to trigger it, >> meaning at some point there is so much data queued to a device the current ring buffer >> can't fit it. >> >> Other possibility is that there were some radix tree changes in 5.10-rc1, haven't looked into those. > > This came with commit > 673d74683627b ("usb: xhci: add debugfs support for ep with stream") > > which is appeared in v5.10-rc1. This hunk below works around it: > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > index 482fe8c5e3b47..699777fb523b6 100644 > --- a/drivers/usb/host/xhci.c > +++ b/drivers/usb/host/xhci.c > @@ -3533,11 +3533,13 @@ static int xhci_alloc_streams(struct usb_hcd *hcd, struct usb_device *udev, > xhci_dbg(xhci, "Slot %u ep ctx %u now has streams.\n", > udev->slot_id, ep_index); > vdev->eps[ep_index].ep_state |= EP_HAS_STREAMS; > - xhci_debugfs_create_stream_files(xhci, vdev, ep_index); > } > xhci_free_command(xhci, config_cmd); > spin_unlock_irqrestore(&xhci->lock, flags); > > + for (i = 0; i < num_eps; i++) > + xhci_debugfs_create_stream_files(xhci, vdev, ep_index); > + > /* Subtract 1 for stream 0, which drivers can't use */ > return num_streams - 1; > Sebastian, I think you might be missing the first mail in this thread. https://lore.kernel.org/linux-usb/20201028203124.375344-4-mathias.nyman@linux.intel.com/ Let me do a quick recap to avoid confusion here. So far we have 2 issues. 1. Lockdep issue #1, stream debugfs entry created with local interrupts disabled and xhci->lock held Cause: 673d74683627b ("usb: xhci: add debugfs support for ep with stream") in v5.10-rc1 Fix: [PATCH 3/3] xhci: Don't create stream debugfs files with spinlock held. (i.e. the mail we are replying to) Comment: easily reproduced, enable lockdep and uas, mount debugfs and connect a UAS device. discovered by both Hans and Mike . 2. Lockdep issue #2, adding entries to radix tree during (stream) ring expansion with interrupts disabled and xhci->lock held. Cause: unknown, probably a patch since we started using radix trees for finding streams Fix: unknown. Comment: Discovered by Mike when testing fix for issue#1. I suspect it can be reproduced on 5.9 but is probably really hard as it involves ring expansion. -Mathias