The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a51a0c8d213594bc094cb8e54aad0cb6d7f7b9a6 Mon Sep 17 00:00:00 2001
From: Clay McClure clay@daemons.net Date: Thu, 21 Sep 2017 19:01:34 -0700 Subject: [PATCH] ubi: Fix race condition between ubi volume creation and udev
Similar to commit 714fb87e8bc0 ("ubi: Fix race condition between ubi device creation and udev"), we should make the volume active before registering it.
Signed-off-by: Clay McClure clay@daemons.net Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger richard@nod.at
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c index 85237cf661f9..3fd8d7ff7a02 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -270,6 +270,12 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) vol->last_eb_bytes = vol->usable_leb_size; }
+ /* Make volume "available" before it becomes accessible via sysfs */ + spin_lock(&ubi->volumes_lock); + ubi->volumes[vol_id] = vol; + ubi->vol_count += 1; + spin_unlock(&ubi->volumes_lock); + /* Register character device for the volume */ cdev_init(&vol->cdev, &ubi_vol_cdev_operations); vol->cdev.owner = THIS_MODULE; @@ -298,11 +304,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) if (err) goto out_sysfs;
- spin_lock(&ubi->volumes_lock); - ubi->volumes[vol_id] = vol; - ubi->vol_count += 1; - spin_unlock(&ubi->volumes_lock); - ubi_volume_notify(ubi, vol, UBI_VOLUME_ADDED); self_check_volumes(ubi); return err; @@ -315,6 +316,10 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) */ cdev_device_del(&vol->cdev, &vol->dev); out_mapping: + spin_lock(&ubi->volumes_lock); + ubi->volumes[vol_id] = NULL; + ubi->vol_count -= 1; + spin_unlock(&ubi->volumes_lock); ubi_eba_destroy_table(eba_tbl); out_acc: spin_lock(&ubi->volumes_lock);