[ 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 <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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
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);