From patchwork Fri Dec 9 01:10:00 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 87359 Delivered-To: patches@linaro.org Received: by 10.140.20.101 with SMTP id 92csp65517qgi; Thu, 8 Dec 2016 17:10:04 -0800 (PST) X-Received: by 10.98.68.84 with SMTP id r81mr76964777pfa.174.1481245804685; Thu, 08 Dec 2016 17:10:04 -0800 (PST) Return-Path: Received: from mail-pf0-x22a.google.com (mail-pf0-x22a.google.com. [2607:f8b0:400e:c00::22a]) by mx.google.com with ESMTPS id b34si31003663pld.128.2016.12.08.17.10.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Dec 2016 17:10:04 -0800 (PST) Received-SPF: pass (google.com: domain of john.stultz@linaro.org designates 2607:f8b0:400e:c00::22a as permitted sender) client-ip=2607:f8b0:400e:c00::22a; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org; spf=pass (google.com: domain of john.stultz@linaro.org designates 2607:f8b0:400e:c00::22a as permitted sender) smtp.mailfrom=john.stultz@linaro.org; dmarc=pass (p=NONE dis=NONE) header.from=linaro.org Received: by mail-pf0-x22a.google.com with SMTP id i88so650638pfk.2 for ; Thu, 08 Dec 2016 17:10:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=id8bMu8y3gyE3hrgCeqlPl93HiW/OacefAGaGI8d+yY=; b=C3+e2VpJt6IMwao50TZi5z8fuoAAt/3QopUjaE66CUkgAU/Y8EwtD7CylayCC1HI3R Aog1PUBykUwPk4NEtW1OToZGNVH1HKa5ReUnwpo5ZtKJIP1HPFYwo4zcfbYz10AIinfr nuHolJlVZBUM5YkarKWDo43u4B/rWW392rpdg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=id8bMu8y3gyE3hrgCeqlPl93HiW/OacefAGaGI8d+yY=; b=gHpJ2dUneHNIIHk1RsAIY/63emqeX9KqkALctRcYyfQLyyJXecQjNZHdG76axBP0uN x1UO2AfuIGyQ6RMg2DQZ45EYvF9OI/eeFjlioXokUKtam/Vv4M/ZeckprTeEwNX2UNBh nCBRQ6LvLRzll7vzruQtiSdWTdtCgHW5gdcwMgJcAtVVQNrJet5ECYVRfkRQ6hSToToG D0lohlembf6Cs7CJDppTYefbnL8QYiryN2KyWAJN6eARr0TjacR6Ujk6a5tcsQezlior 3BTZ2WIr4ItRevnUhZ4g55BpNXDFxslg9mrhNX03tBRVj/zRYPGM69qFnCuu2sQ5koQD 9iOQ== X-Gm-Message-State: AKaTC03btDezjd6pKQC9S7KZ3qWggCxm54T/uVXJwcewAOkCTNtu/M3dLhVfY175RO5Epn+WUYw= X-Received: by 10.99.170.79 with SMTP id x15mr136875916pgo.14.1481245804197; Thu, 08 Dec 2016 17:10:04 -0800 (PST) Return-Path: Received: from localhost.localdomain ([2601:1c2:1002:83f0:4e72:b9ff:fe99:466a]) by smtp.gmail.com with ESMTPSA id q9sm52751451pfg.47.2016.12.08.17.10.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 08 Dec 2016 17:10:03 -0800 (PST) From: John Stultz To: lkml Cc: John Stultz , Wei Xu , Guodong Xu , Amit Pundir , Rob Herring , John Youn , Douglas Anderson , Chen Yu , Kishon Vijay Abraham I , Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org Subject: [RFC][PATCH] usb: dwc2: Avoid sleeping while holding hsotg->lock Date: Thu, 8 Dec 2016 17:10:00 -0800 Message-Id: <1481245800-25369-1-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 2.7.4 Basically when plugging in various cables in different orders, I'm occasionally seeing the following BUG splat: [ 86.215403] BUG: scheduling while atomic: kworker/u16:2/53/0x00000002 [ 86.219164] usb 1-1: USB disconnect, device number 9 [ 86.226845] Preemption disabled at:[ 86.230218] [] dwc2_conn_id_status_change+0x120/0x250 [ 86.236894] CPU: 0 PID: 53 Comm: kworker/u16:2 Tainted: G W 4.9.0-rc8-00051-gd5a7979-dirty #1702 [ 86.246836] Hardware name: HiKey Development Board (DT) [ 86.252100] Workqueue: dwc2 dwc2_conn_id_status_change [ 86.257279] Call trace: [ 86.259771] [] dump_backtrace+0x0/0x1a0 [ 86.265210] [] show_stack+0x14/0x20 [ 86.270308] [] dump_stack+0x90/0xb0 [ 86.275401] [] __schedule_bug+0x6c/0xb8 [ 86.280841] [] __schedule+0x4f8/0x5b0 [ 86.286099] [] schedule+0x38/0xa0 [ 86.291017] [] schedule_hrtimeout_range_clock+0x8c/0xf0 [ 86.297846] [] schedule_hrtimeout_range+0x10/0x18 [ 86.304150] [] usleep_range+0x50/0x58 [ 86.309418] [] dwc2_wait_for_mode.isra.4+0x54/0xd0 [ 86.315815] [] dwc2_core_reset+0xe0/0x168 [ 86.321431] [] dwc2_hsotg_core_init_disconnected+0x2c/0x310 [ 86.328602] [] dwc2_conn_id_status_change+0x130/0x250 [ 86.335254] [] process_one_work+0x118/0x370 [ 86.341035] [] worker_thread+0x48/0x498 [ 86.346473] [] kthread+0xd0/0xe8 [ 86.351299] [] ret_from_fork+0x10/0x50 This seems to be caused by the dwc2_wait_for_mode() calling usleep_range() while the hstog->lock spinlock is held, since we take that before calling dwc2_hsotg_core_init_disconnected(). This patch avoids the issue by adding an extra argument to dwc2_core_reset(), as suggested by John Youn, which allows us to skip the waiting, which should be unnecessary when calling from dwc2_hsotg_core_init_disconnected(). Cc: Wei Xu Cc: Guodong Xu Cc: Amit Pundir Cc: Rob Herring Cc: John Youn Cc: Douglas Anderson Cc: Chen Yu Cc: Kishon Vijay Abraham I Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org Signed-off-by: John Stultz --- drivers/usb/dwc2/core.c | 6 +++--- drivers/usb/dwc2/core.h | 2 +- drivers/usb/dwc2/gadget.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) -- 2.7.4 diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c index 4c0fa0b..2e83545 100644 --- a/drivers/usb/dwc2/core.c +++ b/drivers/usb/dwc2/core.c @@ -313,7 +313,7 @@ static bool dwc2_iddig_filter_enabled(struct dwc2_hsotg *hsotg) * Do core a soft reset of the core. Be careful with this because it * resets all the internal state machines of the core. */ -int dwc2_core_reset(struct dwc2_hsotg *hsotg) +int dwc2_core_reset(struct dwc2_hsotg *hsotg, bool skip_wait) { u32 greset; int count = 0; @@ -369,7 +369,7 @@ int dwc2_core_reset(struct dwc2_hsotg *hsotg) } } while (!(greset & GRSTCTL_AHBIDLE)); - if (wait_for_host_mode) + if (wait_for_host_mode && !skip_wait) dwc2_wait_for_mode(hsotg, true); return 0; @@ -500,7 +500,7 @@ int dwc2_core_reset_and_force_dr_mode(struct dwc2_hsotg *hsotg) { int retval; - retval = dwc2_core_reset(hsotg); + retval = dwc2_core_reset(hsotg, false); if (retval) return retval; diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h index 2a21a04..963ea1b 100644 --- a/drivers/usb/dwc2/core.h +++ b/drivers/usb/dwc2/core.h @@ -1020,7 +1020,7 @@ enum dwc2_halt_status { * The following functions support initialization of the core driver component * and the DWC_otg controller */ -extern int dwc2_core_reset(struct dwc2_hsotg *hsotg); +extern int dwc2_core_reset(struct dwc2_hsotg *hsotg, bool skip_wait); extern int dwc2_core_reset_and_force_dr_mode(struct dwc2_hsotg *hsotg); extern int dwc2_enter_hibernation(struct dwc2_hsotg *hsotg); extern int dwc2_exit_hibernation(struct dwc2_hsotg *hsotg, bool restore); diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c index 24fbebc..0bda799 100644 --- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -2521,7 +2521,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg, kill_all_requests(hsotg, hsotg->eps_out[0], -ECONNRESET); if (!is_usb_reset) - if (dwc2_core_reset(hsotg)) + if (dwc2_core_reset(hsotg, true)) return; /*