From patchwork Mon Mar 14 19:19:16 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 8583641 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 050E09F54C for ; Mon, 14 Mar 2016 19:19:49 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 13D4720204 for ; Mon, 14 Mar 2016 19:19:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E32820270 for ; Mon, 14 Mar 2016 19:19:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932171AbcCNTTi (ORCPT ); Mon, 14 Mar 2016 15:19:38 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:35874 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932069AbcCNTTf (ORCPT ); Mon, 14 Mar 2016 15:19:35 -0400 Received: from [191.33.151.62] (helo=smtp.w2.samsung.com) by bombadil.infradead.org with esmtpsa (Exim 4.80.1 #2 (Red Hat Linux)) id 1afY1e-0006OZ-Fh; Mon, 14 Mar 2016 19:19:34 +0000 Received: from mchehab by smtp.w2.samsung.com with local (Exim 4.86_2) (envelope-from ) id 1afY1c-0008Ft-0K; Mon, 14 Mar 2016 16:19:32 -0300 From: Mauro Carvalho Chehab To: Linux Media Mailing List Cc: Mauro Carvalho Chehab , Mauro Carvalho Chehab , Shuah Khan Subject: [PATCH v2] [media] media-device: Don't call notify callbacks holding a spinlock Date: Mon, 14 Mar 2016 16:19:16 -0300 Message-Id: X-Mailer: git-send-email 2.5.0 In-Reply-To: <31ecc9d6d2f29b0bd76c03c516d12aa7d0be2f66.1457982982.git.mchehab@osg.samsung.com> References: <31ecc9d6d2f29b0bd76c03c516d12aa7d0be2f66.1457982982.git.mchehab@osg.samsung.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The notify routines may sleep. So, they can't be called in spinlock context. Also, they may want to call other media routines that might be spinning the spinlock, like creating a link. This fixes the following bug: [ 1839.510587] BUG: sleeping function called from invalid context at mm/slub.c:1289 [ 1839.510881] in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe [ 1839.511157] 4 locks held by modprobe/3479: [ 1839.511415] #0: (&dev->mutex){......}, at: [] __driver_attach+0xa3/0x160 [ 1839.512381] #1: (&dev->mutex){......}, at: [] __driver_attach+0xb1/0x160 [ 1839.512388] #2: (register_mutex#5){+.+.+.}, at: [] usb_audio_probe+0x257/0x1c90 [snd_usb_audio] [ 1839.512401] #3: (&(&mdev->lock)->rlock){+.+.+.}, at: [] media_device_register_entity+0x1cb/0x700 [media] [ 1839.512412] CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49 [ 1839.512415] Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015 [ 1839.512417] 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000 [ 1839.512422] ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000 [ 1839.512427] ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5 [ 1839.512432] Call Trace: [ 1839.512436] [] dump_stack+0x85/0xc4 [ 1839.512440] [] ___might_sleep+0x245/0x3a0 [ 1839.512443] [] __might_sleep+0x95/0x1a0 [ 1839.512446] [] kmem_cache_alloc_trace+0x20e/0x300 [ 1839.512451] [] ? media_add_link+0x4d/0x140 [media] [ 1839.512455] [] media_add_link+0x4d/0x140 [media] [ 1839.512459] [] media_create_pad_link+0xa1/0x600 [media] [ 1839.512463] [] au0828_media_graph_notify+0x173/0x360 [au0828] [ 1839.512467] [] ? media_gobj_create+0x1ba/0x480 [media] [ 1839.512471] [] media_device_register_entity+0x3ab/0x700 [media] Tested with an HVR-950Q, under the following testcases: 1) load au0828 driver first, and then snd-usb-audio; 2) load snd-usb-audio driver first, and then au0828; 3) loading both drivers, and then connecting the device. Signed-off-by: Mauro Carvalho Chehab Tested-by: Shuah Khan --- Please disconsider verison 1. It got amended with an experimental patch. drivers/media/media-device.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index 6ba6e8f982fc..fc3c199e5500 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -587,14 +587,15 @@ int __must_check media_device_register_entity(struct media_device *mdev, media_gobj_create(mdev, MEDIA_GRAPH_PAD, &entity->pads[i].graph_obj); + spin_unlock(&mdev->lock); + /* invoke entity_notify callbacks */ list_for_each_entry_safe(notify, next, &mdev->entity_notify, list) { (notify)->notify(entity, notify->notify_data); } - spin_unlock(&mdev->lock); - mutex_lock(&mdev->graph_mutex); + if (mdev->entity_internal_idx_max >= mdev->pm_count_walk.ent_enum.idx_max) { struct media_entity_graph new = { .top = 0 };