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FAILED: patch "[PATCH] ubi: Fix race condition between ubi volume creation and udev" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Feb 14, 2018

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Stable branch Memory technology devices (MTD) Unsorted block images (UBI)
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The patch below does not apply to the 4.9-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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From a51a0c8d213594bc094cb8e54aad0cb6d7f7b9a6 Mon Sep 17 00:00:00 2001

From: Clay McClure <[email protected]>
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 <[email protected]>
Cc <[email protected]>
Signed-off-by Richard Weinberger <[email protected]>
drivers/mtd/ubi/vmt.c +10 -5
index 85237cf661f9..3fd8d7ff7a02 100644
@@ -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);