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 912F3C54EBE for ; Mon, 16 Jan 2023 17:30:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234796AbjAPRap (ORCPT ); Mon, 16 Jan 2023 12:30:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234833AbjAPR34 (ORCPT ); Mon, 16 Jan 2023 12:29:56 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBED43A854 for ; Mon, 16 Jan 2023 09:07:26 -0800 (PST) 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 36ADDB81091 for ; Mon, 16 Jan 2023 17:07:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CFCCC433EF; Mon, 16 Jan 2023 17:07:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673888843; bh=z3ZCtXUpciX2ZVdgUt2vhDPs4ZMsOvQLQuxD575qTbo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BVI6xHLe0wiZqhlWMdVSOcyY5Lq1i/Xt/wUEX+nG/CLHeHlY4QY6draCrkWjKYMAG 9kpERE8IWONhTomFRlCoaHHG9judNUz+1h8xhPB9a7KkqA1v9FX5xvoXS5ADy7nf6G cwoEfgLww12+VXmRF2En0EQa3cqYkZZQvSsPhITc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rafael Mendonca , Sasha Levin Subject: [PATCH 4.14 161/338] uio: uio_dmem_genirq: Fix deadlock between irq config and handling Date: Mon, 16 Jan 2023 16:50:34 +0100 Message-Id: <20230116154827.911696053@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154820.689115727@linuxfoundation.org> References: <20230116154820.689115727@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rafael Mendonca [ Upstream commit 118b918018175d9fcd8db667f905012e986cc2c9 ] This fixes a concurrency issue addressed in commit 34cb27528398 ("UIO: Fix concurrency issue"): "In a SMP case there was a race condition issue between Uio_pdrv_genirq_irqcontrol() running on one CPU and irq handler on another CPU. Fix it by spin_locking shared resources access inside irq handler." The implementation of "uio_dmem_genirq" was based on "uio_pdrv_genirq" and it is used in a similar manner to the "uio_pdrv_genirq" driver with respect to interrupt configuration and handling. At the time "uio_dmem_genirq" was merged, both had the same implementation of the 'uio_info' handlers irqcontrol() and handler(), thus, both had the same concurrency issue mentioned by the above commit. However, the above patch was only applied to the "uio_pdrv_genirq" driver. Split out from commit 34cb27528398 ("UIO: Fix concurrency issue"). Fixes: 0a0c3b5a24bd ("Add new uio device for dynamic memory allocation") Signed-off-by: Rafael Mendonca Link: https://lore.kernel.org/r/20220930224100.816175-3-rafaelmendsr@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/uio/uio_dmem_genirq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c index c25a6bcb2d21..b4b7fa05b29b 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -113,8 +113,10 @@ static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info) * remember the state so we can allow user space to enable it later. */ + spin_lock(&priv->lock); if (!test_and_set_bit(0, &priv->flags)) disable_irq_nosync(irq); + spin_unlock(&priv->lock); return IRQ_HANDLED; } @@ -128,7 +130,8 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) * in the interrupt controller, but keep track of the * state to prevent per-irq depth damage. * - * Serialize this operation to support multiple tasks. + * Serialize this operation to support multiple tasks and concurrency + * with irq handler on SMP systems. */ spin_lock_irqsave(&priv->lock, flags); -- 2.35.1