From patchwork Mon Mar 24 02:38:10 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 3880981 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D125A9F334 for ; Mon, 24 Mar 2014 02:39:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E963020160 for ; Mon, 24 Mar 2014 02:39:08 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 77DEE2012D for ; Mon, 24 Mar 2014 02:39:07 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WRumq-00028F-EP; Mon, 24 Mar 2014 02:38:52 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WRumn-0002IY-Uc; Mon, 24 Mar 2014 02:38:49 +0000 Received: from mail-out.m-online.net ([212.18.0.10]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WRumj-0002IB-Qe for linux-arm-kernel@lists.infradead.org; Mon, 24 Mar 2014 02:38:47 +0000 Received: from frontend1.mail.m-online.net (frontend1.mail.intern.m-online.net [192.168.8.180]) by mail-out.m-online.net (Postfix) with ESMTP id 3fsfsT34Sfz3hhcN; Mon, 24 Mar 2014 03:38:21 +0100 (CET) X-Auth-Info: 1JizfJ/t0z6YQFvh51fAlWz5WJTKUZfZ6U6/nytUAVc= Received: from chi.lan (unknown [195.140.253.167]) by smtp-auth.mnet-online.de (Postfix) with ESMTPA id 3fsfsT1khfzbbcl; Mon, 24 Mar 2014 03:38:21 +0100 (CET) From: Marek Vasut To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] gpio: mxs: Allow for recursive enable_irq_wake() call Date: Mon, 24 Mar 2014 03:38:10 +0100 Message-Id: <1395628690-7225-1-git-send-email-marex@denx.de> X-Mailer: git-send-email 1.8.5.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140323_223846_080708_ED4744FB X-CRM114-Status: GOOD ( 12.57 ) X-Spam-Score: -1.9 (-) Cc: Marek Vasut , Linus Walleij , Shawn Guo X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 scenario here is that someone calls enable_irq_wake() from somewhere in the code. This will result in the lockdep producing a backtrace as can be seen below. In my case, this problem is triggered when using the wl1271 (TI WlCore) driver found in drivers/net/wireless/ti/ . The problem cause is rather obvious from the backtrace, but let's outline the dependency. enable_irq_wake() grabs the IRQ buslock in irq_set_irq_wake(), which in turns calls mxs_gpio_set_wake_irq() . But mxs_gpio_set_wake_irq() calls enable_irq_wake() again on the one-level-higher IRQ , thus it tries to grab the IRQ buslock again in irq_set_irq_wake() . Because the spinlock in irq_set_irq_wake()->irq_get_desc_buslock()->__irq_get_desc_lock() is not marked as recursive, lockdep will spew the stuff below. We know we can safely re-enter the lock, so use IRQ_GC_INIT_NESTED_LOCK to fix the spew. ============================================= [ INFO: possible recursive locking detected ] 3.10.33-00012-gf06b763-dirty #61 Not tainted --------------------------------------------- kworker/0:1/18 is trying to acquire lock: (&irq_desc_lock_class){-.-...}, at: [] __irq_get_desc_lock+0x48/0x88 but task is already holding lock: (&irq_desc_lock_class){-.-...}, at: [] __irq_get_desc_lock+0x48/0x88 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&irq_desc_lock_class); lock(&irq_desc_lock_class); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/0:1/18: #0: (events){.+.+.+}, at: [] process_one_work+0x134/0x4a4 #1: ((&fw_work->work)){+.+.+.}, at: [] process_one_work+0x134/0x4a4 #2: (&irq_desc_lock_class){-.-...}, at: [] __irq_get_desc_lock+0x48/0x88 stack backtrace: CPU: 0 PID: 18 Comm: kworker/0:1 Not tainted 3.10.33-00012-gf06b763-dirty #61 Workqueue: events request_firmware_work_func [] (unwind_backtrace+0x0/0xf0) from [] (show_stack+0x10/0x14) [] (show_stack+0x10/0x14) from [] (__lock_acquire+0x140c/0x1a64) [] (__lock_acquire+0x140c/0x1a64) from [] (lock_acquire+0x9c/0x104) [] (lock_acquire+0x9c/0x104) from [] (_raw_spin_lock_irqsave+0x44/0x58) [] (_raw_spin_lock_irqsave+0x44/0x58) from [] (__irq_get_desc_lock+0x48/0x88) [] (__irq_get_desc_lock+0x48/0x88) from [] (irq_set_irq_wake+0x20/0xf4) [] (irq_set_irq_wake+0x20/0xf4) from [] (mxs_gpio_set_wake_irq+0x1c/0x24) [] (mxs_gpio_set_wake_irq+0x1c/0x24) from [] (set_irq_wake_real+0x30/0x44) [] (set_irq_wake_real+0x30/0x44) from [] (irq_set_irq_wake+0x8c/0xf4) [] (irq_set_irq_wake+0x8c/0xf4) from [] (wlcore_nvs_cb+0x10c/0x97c) [] (wlcore_nvs_cb+0x10c/0x97c) from [] (request_firmware_work_func+0x38/0x58) [] (request_firmware_work_func+0x38/0x58) from [] (process_one_work+0x1c0/0x4a4) [] (process_one_work+0x1c0/0x4a4) from [] (worker_thread+0x138/0x394) [] (worker_thread+0x138/0x394) from [] (kthread+0xa4/0xb0) [] (kthread+0xa4/0xb0) from [] (ret_from_fork+0x14/0x34) wlcore: loaded Signed-off-by: Marek Vasut Cc: Shawn Guo Cc: Linus Walleij Acked-by: Shawn Guo --- drivers/gpio/gpio-mxs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) NOTE 1: I think this should go into -stable as well eventually. NOTE 2: I developed this on 3.10.33, but I still see this is not fixed in -next. diff --git a/drivers/gpio/gpio-mxs.c b/drivers/gpio/gpio-mxs.c index f8e6af2..d599fc4 100644 --- a/drivers/gpio/gpio-mxs.c +++ b/drivers/gpio/gpio-mxs.c @@ -214,7 +214,8 @@ static void __init mxs_gpio_init_gc(struct mxs_gpio_port *port, int irq_base) ct->regs.ack = PINCTRL_IRQSTAT(port) + MXS_CLR; ct->regs.mask = PINCTRL_IRQEN(port); - irq_setup_generic_chip(gc, IRQ_MSK(32), 0, IRQ_NOREQUEST, 0); + irq_setup_generic_chip(gc, IRQ_MSK(32), IRQ_GC_INIT_NESTED_LOCK, + IRQ_NOREQUEST, 0); } static int mxs_gpio_to_irq(struct gpio_chip *gc, unsigned offset)