From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:55654 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727069AbfICQcM (ORCPT ); Tue, 3 Sep 2019 12:32:12 -0400 From: Sasha Levin Subject: [PATCH AUTOSEL 4.19 162/167] virtio/s390: fix race on airq_areas[] Date: Tue, 3 Sep 2019 12:25:14 -0400 Message-Id: <20190903162519.7136-162-sashal@kernel.org> In-Reply-To: <20190903162519.7136-1-sashal@kernel.org> References: <20190903162519.7136-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Halil Pasic , Marc Hartmayer , Cornelia Huck , Heiko Carstens , Sasha Levin , linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org From: Halil Pasic [ Upstream commit 4f419eb14272e0698e8c55bb5f3f266cc2a21c81 ] The access to airq_areas was racy ever since the adapter interrupts got introduced to virtio-ccw, but since commit 39c7dcb15892 ("virtio/s390: make airq summary indicators DMA") this became an issue in practice as well. Namely before that commit the airq_info that got overwritten was still functional. After that commit however the two infos share a summary_indicator, which aggravates the situation. Which means auto-online mechanism occasionally hangs the boot with virtio_blk. Signed-off-by: Halil Pasic Reported-by: Marc Hartmayer Reviewed-by: Cornelia Huck Cc: stable@vger.kernel.org Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.") Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- drivers/s390/virtio/virtio_ccw.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index ec54538f7ae1c..67efdf25657f3 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -132,6 +132,7 @@ struct airq_info { struct airq_iv *aiv; }; static struct airq_info *airq_areas[MAX_AIRQ_AREAS]; +static DEFINE_MUTEX(airq_areas_lock); #define CCW_CMD_SET_VQ 0x13 #define CCW_CMD_VDEV_RESET 0x33 @@ -244,9 +245,11 @@ static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs, unsigned long bit, flags; for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) { + mutex_lock(&airq_areas_lock); if (!airq_areas[i]) airq_areas[i] = new_airq_info(); info = airq_areas[i]; + mutex_unlock(&airq_areas_lock); if (!info) return 0; write_lock_irqsave(&info->lock, flags); -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.19 162/167] virtio/s390: fix race on airq_areas[] Date: Tue, 3 Sep 2019 12:25:14 -0400 Message-ID: <20190903162519.7136-162-sashal@kernel.org> References: <20190903162519.7136-1-sashal@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190903162519.7136-1-sashal@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sasha Levin , linux-s390@vger.kernel.org, kvm@vger.kernel.org, Cornelia Huck , Heiko Carstens , virtualization@lists.linux-foundation.org, Halil Pasic , Marc Hartmayer List-Id: virtualization@lists.linuxfoundation.org From: Halil Pasic [ Upstream commit 4f419eb14272e0698e8c55bb5f3f266cc2a21c81 ] The access to airq_areas was racy ever since the adapter interrupts got introduced to virtio-ccw, but since commit 39c7dcb15892 ("virtio/s390: make airq summary indicators DMA") this became an issue in practice as well. Namely before that commit the airq_info that got overwritten was still functional. After that commit however the two infos share a summary_indicator, which aggravates the situation. Which means auto-online mechanism occasionally hangs the boot with virtio_blk. Signed-off-by: Halil Pasic Reported-by: Marc Hartmayer Reviewed-by: Cornelia Huck Cc: stable@vger.kernel.org Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.") Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- drivers/s390/virtio/virtio_ccw.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index ec54538f7ae1c..67efdf25657f3 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -132,6 +132,7 @@ struct airq_info { struct airq_iv *aiv; }; static struct airq_info *airq_areas[MAX_AIRQ_AREAS]; +static DEFINE_MUTEX(airq_areas_lock); #define CCW_CMD_SET_VQ 0x13 #define CCW_CMD_VDEV_RESET 0x33 @@ -244,9 +245,11 @@ static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs, unsigned long bit, flags; for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) { + mutex_lock(&airq_areas_lock); if (!airq_areas[i]) airq_areas[i] = new_airq_info(); info = airq_areas[i]; + mutex_unlock(&airq_areas_lock); if (!info) return 0; write_lock_irqsave(&info->lock, flags); -- 2.20.1