From patchwork Fri Mar 6 16:37:43 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 5956451 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 [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 10B549F749 for ; Fri, 6 Mar 2015 16:42:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 32DB920396 for ; Fri, 6 Mar 2015 16:42:16 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (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 4E0912038D for ; Fri, 6 Mar 2015 16:42:15 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YTvHe-0001LB-KY; Fri, 06 Mar 2015 16:39:30 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YTvGe-0000q8-Vd for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2015 16:38:29 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C284C2993; Fri, 6 Mar 2015 08:38:27 -0800 (PST) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.209.148]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F18B93F5FA; Fri, 6 Mar 2015 08:38:04 -0800 (PST) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 04/11] irqchip: gicv3-its: Fix unsafe locking reported by lockdep Date: Fri, 6 Mar 2015 16:37:43 +0000 Message-Id: <1425659870-11832-5-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1425659870-11832-1-git-send-email-marc.zyngier@arm.com> References: <1425659870-11832-1-git-send-email-marc.zyngier@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150306_083829_208136_5172F31C X-CRM114-Status: GOOD ( 10.90 ) X-Spam-Score: -0.0 (/) Cc: Thomas Gleixner , Vladimir Murzin , Will Deacon , Jason Cooper , Yun Wu X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 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=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_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 When compiled with CONFIG_LOCKDEP, the kernel shouts badly, saying that my locking is unsafe. I'm afraid the kernel is right: CPU0 CPU1 ---- ---- lock(&its->lock); local_irq_disable(); lock(&irq_desc_lock_class); lock(&its->lock); lock(&irq_desc_lock_class); *** DEADLOCK *** The fix is to always take its->lock with interrupts disabled. Reported-by: Will Deacon Signed-off-by: Marc Zyngier --- drivers/irqchip/irq-gic-v3-its.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 46b9441..6850141 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -416,13 +416,14 @@ static void its_send_single_command(struct its_node *its, { struct its_cmd_block *cmd, *sync_cmd, *next_cmd; struct its_collection *sync_col; + unsigned long flags; - raw_spin_lock(&its->lock); + raw_spin_lock_irqsave(&its->lock, flags); cmd = its_allocate_entry(its); if (!cmd) { /* We're soooooo screewed... */ pr_err_ratelimited("ITS can't allocate, dropping command\n"); - raw_spin_unlock(&its->lock); + raw_spin_unlock_irqrestore(&its->lock, flags); return; } sync_col = builder(cmd, desc); @@ -442,7 +443,7 @@ static void its_send_single_command(struct its_node *its, post: next_cmd = its_post_commands(its); - raw_spin_unlock(&its->lock); + raw_spin_unlock_irqrestore(&its->lock, flags); its_wait_for_range_completion(its, cmd, next_cmd); } @@ -1037,8 +1038,9 @@ static void its_cpu_init_collection(void) static struct its_device *its_find_device(struct its_node *its, u32 dev_id) { struct its_device *its_dev = NULL, *tmp; + unsigned long flags; - raw_spin_lock(&its->lock); + raw_spin_lock_irqsave(&its->lock, flags); list_for_each_entry(tmp, &its->its_device_list, entry) { if (tmp->device_id == dev_id) { @@ -1047,7 +1049,7 @@ static struct its_device *its_find_device(struct its_node *its, u32 dev_id) } } - raw_spin_unlock(&its->lock); + raw_spin_unlock_irqrestore(&its->lock, flags); return its_dev; } @@ -1057,6 +1059,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id, { struct its_device *dev; unsigned long *lpi_map; + unsigned long flags; void *itt; int lpi_base; int nr_lpis; @@ -1092,9 +1095,9 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id, dev->device_id = dev_id; INIT_LIST_HEAD(&dev->entry); - raw_spin_lock(&its->lock); + raw_spin_lock_irqsave(&its->lock, flags); list_add(&dev->entry, &its->its_device_list); - raw_spin_unlock(&its->lock); + raw_spin_unlock_irqrestore(&its->lock, flags); /* Bind the device to the first possible CPU */ cpu = cpumask_first(cpu_online_mask); @@ -1108,9 +1111,11 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id, static void its_free_device(struct its_device *its_dev) { - raw_spin_lock(&its_dev->its->lock); + unsigned long flags; + + raw_spin_lock_irqsave(&its_dev->its->lock, flags); list_del(&its_dev->entry); - raw_spin_unlock(&its_dev->its->lock); + raw_spin_unlock_irqrestore(&its_dev->its->lock, flags); kfree(its_dev->itt); kfree(its_dev); }