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authorHalil Pasic <pasic@linux.ibm.com>2019-07-23 17:11:01 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2019-07-26 13:36:18 +0200
commit4f419eb14272e0698e8c55bb5f3f266cc2a21c81 (patch)
tree104319c03391b176c77080df0292e26f7394a8a7 /drivers/s390/virtio
parents390/dma: provide proper ARCH_ZONE_DMA_BITS value (diff)
downloadlinux-dev-4f419eb14272e0698e8c55bb5f3f266cc2a21c81.tar.xz
linux-dev-4f419eb14272e0698e8c55bb5f3f266cc2a21c81.zip
virtio/s390: fix race on airq_areas[]
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 <pasic@linux.ibm.com> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Cc: stable@vger.kernel.org Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.") Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'drivers/s390/virtio')
-rw-r--r--drivers/s390/virtio/virtio_ccw.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 1a55e5942d36..957889a42d2e 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -145,6 +145,8 @@ struct airq_info {
struct airq_iv *aiv;
};
static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
+static DEFINE_MUTEX(airq_areas_lock);
+
static u8 *summary_indicators;
static inline u8 *get_summary_indicator(struct airq_info *info)
@@ -265,9 +267,11 @@ 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(i);
info = airq_areas[i];
+ mutex_unlock(&airq_areas_lock);
if (!info)
return 0;
write_lock_irqsave(&info->lock, flags);