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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2BB7C3F36B for ; Thu, 27 Feb 2020 13:54:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9714721D7E for ; Thu, 27 Feb 2020 13:54:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811686; bh=k+XzV/W9UPSf5JZG4LsaLccqrAu0LZ7Ag9WTLrAZBPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I1sll0NSQwzI9spjeJIGR8A7TNMjW47OD2I3MF9RpAzOqZ9Lv88L7qYKge20Y3s35 o50B7RqgHXT6vcfWHcsgvf/w2eJCbl27e3XaCHL3hrBCVK9yUNlXON7fA8/BAfXBvP qPNKWB/0oMfRvRWtaQMhxdFsLI0BNwrnz0TU//9w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731900AbgB0Nyo (ORCPT ); Thu, 27 Feb 2020 08:54:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:54658 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731851AbgB0Nye (ORCPT ); Thu, 27 Feb 2020 08:54:34 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AE63A20578; Thu, 27 Feb 2020 13:54:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811673; bh=k+XzV/W9UPSf5JZG4LsaLccqrAu0LZ7Ag9WTLrAZBPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0l8QRQEB3z2Ec1AxKNGuNCtjcvdDlnYmOATLeZYimimbkJdFLKsxeI5ibMDJ9fbbn nWC4YSSJCJNKyT8NM/5U64djGANw5Zx+BbfYOuJWlc4jkMVMM/VBOWeAraqonsdLIY XuDuSZgq+UBlbzBHuneFRpsVQPdB+06ywSZyX7wM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jia-Ju Bai , Sasha Levin Subject: [PATCH 4.14 057/237] uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol() Date: Thu, 27 Feb 2020 14:34:31 +0100 Message-Id: <20200227132301.094280994@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jia-Ju Bai [ Upstream commit b74351287d4bd90636c3f48bc188c2f53824c2d4 ] The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: kernel/irq/manage.c, 523: synchronize_irq in disable_irq drivers/uio/uio_dmem_genirq.c, 140: disable_irq in uio_dmem_genirq_irqcontrol drivers/uio/uio_dmem_genirq.c, 134: _raw_spin_lock_irqsave in uio_dmem_genirq_irqcontrol synchronize_irq() can sleep at runtime. To fix this bug, disable_irq() is called without holding the spinlock. This bug is found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai Link: https://lore.kernel.org/r/20191218094405.6009-1-baijiaju1990@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/uio/uio_dmem_genirq.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c index e1134a4d97f3f..a00b4aee6c799 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -135,11 +135,13 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) if (irq_on) { if (test_and_clear_bit(0, &priv->flags)) enable_irq(dev_info->irq); + spin_unlock_irqrestore(&priv->lock, flags); } else { - if (!test_and_set_bit(0, &priv->flags)) + if (!test_and_set_bit(0, &priv->flags)) { + spin_unlock_irqrestore(&priv->lock, flags); disable_irq(dev_info->irq); + } } - spin_unlock_irqrestore(&priv->lock, flags); return 0; } -- 2.20.1