On Mon, Oct 15, 2018 at 03:25:08PM +0200, Vasilis Liaskovitis wrote: > If a block device is hot-added when we are out of grants, > gnttab_grant_foreign_access fails with -ENOSPC (log message "28 > granting access to ring page") in this code path: > > talk_to_blkback -> > setup_blkring -> > xenbus_grant_ring -> > gnttab_grant_foreign_access > > and the failing path in talk_to_blkback sets the driver_data to NULL: > > destroy_blkring: > blkif_free(info, 0); > > mutex_lock(&blkfront_mutex); > free_info(info); > mutex_unlock(&blkfront_mutex); > > dev_set_drvdata(&dev->dev, NULL); > > This results in a NULL pointer BUG when blkfront_remove and blkif_free > try to access the failing device's NULL struct blkfront_info. > > Signed-off-by: Vasilis Liaskovitis <vliaskovitis@xxxxxxxx> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> Thanks. I guess this is a candidate for backporting?
