From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9C86749D for ; Thu, 12 Jan 2023 14:17:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FE80C433D2; Thu, 12 Jan 2023 14:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673533025; bh=QcPpNKho0NZh59biSdf3ePMt6Cq+2jABvWyt1PQm644=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YW9V++3vKT+U/au59dldPIePoTySVNtwJdqq7fUC7xjA+2urGKfDOvMITo30nWfeu Kx0/RLmwbTjl67ddFAXSv8DvFQX2ibtmYM7hprY/XIIWQmPojjRGOOQp6LxdEwU9t7 jIzPSkcbQDu2K57p/GsEg4y5b2j8ZWduJeG4tCOc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rafael Mendonca , Sasha Levin Subject: [PATCH 5.10 346/783] uio: uio_dmem_genirq: Fix deadlock between irq config and handling Date: Thu, 12 Jan 2023 14:51:02 +0100 Message-Id: <20230112135540.360691577@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230112135524.143670746@linuxfoundation.org> References: <20230112135524.143670746@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 796946bab508..92751737bbea 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -110,8 +110,10 @@ 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; } @@ -125,7 +127,8 @@ 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