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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59896C433F5 for ; Thu, 14 Apr 2022 14:00:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345877AbiDNNyh (ORCPT ); Thu, 14 Apr 2022 09:54:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245620AbiDNN3K (ORCPT ); Thu, 14 Apr 2022 09:29:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 680D3939A4; Thu, 14 Apr 2022 06:23:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 11A93B82910; Thu, 14 Apr 2022 13:23:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53F27C385A1; Thu, 14 Apr 2022 13:23:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649942598; bh=HAjsokNLpm1BGeHXA8hl2TeS4FY5QiuvnC9KI1mxvmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lmpDPvIYQjgV9R3rGXa+VjSy40DQSHiJwuP68rgU6g9bwqb8frD2MpCYIPAESIeme iayGSYTgPeJAxz7tG3jHfzrBGA2jZ2+i31hSt4E5p7dLNWDez3EGN/AKK2BUjDBJK5 +pxixXjY+lF5Q8u5O9xJxq2yt88l+FlK4w4ERbY4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Maulik Shah , Sasha Levin Subject: [PATCH 4.19 191/338] irqchip/qcom-pdc: Fix broken locking Date: Thu, 14 Apr 2022 15:11:34 +0200 Message-Id: <20220414110844.332100972@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110838.883074566@linuxfoundation.org> References: <20220414110838.883074566@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Zyngier [ Upstream commit a6aca2f460e203781dc41391913cc5b54f4bc0ce ] pdc_enable_intr() serves as a primitive to qcom_pdc_gic_{en,dis}able, and has a raw spinlock for mutual exclusion, which is uses with interruptible primitives. This means that this critical section can itself be interrupted. Should the interrupt also be a PDC interrupt, and the endpoint driver perform an irq_disable() on that interrupt, we end-up in a deadlock. Fix this by using the irqsave/irqrestore variants of the locking primitives. Signed-off-by: Marc Zyngier Reviewed-by: Maulik Shah Link: https://lore.kernel.org/r/20220224101226.88373-5-maz@kernel.org Signed-off-by: Sasha Levin --- drivers/irqchip/qcom-pdc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c index faa7d61b9d6c..239a889df608 100644 --- a/drivers/irqchip/qcom-pdc.c +++ b/drivers/irqchip/qcom-pdc.c @@ -50,17 +50,18 @@ static u32 pdc_reg_read(int reg, u32 i) static void pdc_enable_intr(struct irq_data *d, bool on) { int pin_out = d->hwirq; + unsigned long flags; u32 index, mask; u32 enable; index = pin_out / 32; mask = pin_out % 32; - raw_spin_lock(&pdc_lock); + raw_spin_lock_irqsave(&pdc_lock, flags); enable = pdc_reg_read(IRQ_ENABLE_BANK, index); enable = on ? ENABLE_INTR(enable, mask) : CLEAR_INTR(enable, mask); pdc_reg_write(IRQ_ENABLE_BANK, index, enable); - raw_spin_unlock(&pdc_lock); + raw_spin_unlock_irqrestore(&pdc_lock, flags); } static void qcom_pdc_gic_mask(struct irq_data *d) -- 2.34.1