[PATCH 2/2] ubi: free the normal volumes in error paths of ubi_attach_mtd_dev()

Hou Tao houtao1 at huawei.com
Sat Nov 30 01:48:25 PST 2019


The allocated normal volumes saved in ubi->volumes are not freed
in the error paths in ubi_attach_mtd_dev() and its callees (e.g.
ubi_attach() and ubi_read_volume_table()).

These normal volumes should be freed through kill_volumes() and
vol_release(), but ubi_attach_mtd_dev() may fail before
calling uif_init(), and there will be memory leaks.

So adding a new helper ubi_free_all_volumes() to free the normal
and the internal volumes. And in order to prevent double-free
of volume, reset ubi->volumes[i] to NULL after freeing.

Signed-off-by: Hou Tao <houtao1 at huawei.com>
---
 drivers/mtd/ubi/attach.c |  2 +-
 drivers/mtd/ubi/build.c  | 31 ++++++++++++++++++++++++++-----
 drivers/mtd/ubi/ubi.h    |  1 +
 drivers/mtd/ubi/vtbl.c   | 10 ++--------
 4 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index 10b2459f8951..ea7440ac913b 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -1640,7 +1640,7 @@ int ubi_attach(struct ubi_device *ubi, int force_scan)
 out_wl:
 	ubi_wl_close(ubi);
 out_vtbl:
-	ubi_free_internal_volumes(ubi);
+	ubi_free_all_volumes(ubi);
 	vfree(ubi->vtbl);
 out_ai:
 	destroy_ai(ai);
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index d636bbe214cb..25fb72b2efa0 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -503,21 +503,42 @@ static void uif_close(struct ubi_device *ubi)
 }
 
 /**
- * ubi_free_internal_volumes - free internal volumes.
+ * ubi_free_volumes_from - free volumes from specific index.
  * @ubi: UBI device description object
+ * @from: the start index used for volume free.
  */
-void ubi_free_internal_volumes(struct ubi_device *ubi)
+static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
 {
 	int i;
 
-	for (i = ubi->vtbl_slots;
-	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
+	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
+		if (!ubi->volumes[i])
+			continue;
 		ubi_eba_replace_table(ubi->volumes[i], NULL);
 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
 		kfree(ubi->volumes[i]);
+		ubi->volumes[i] = NULL;
 	}
 }
 
+/**
+ * ubi_free_all_volumes - free all volumes.
+ * @ubi: UBI device description object
+ */
+void ubi_free_all_volumes(struct ubi_device *ubi)
+{
+	ubi_free_volumes_from(ubi, 0);
+}
+
+/**
+ * ubi_free_internal_volumes - free internal volumes.
+ * @ubi: UBI device description object
+ */
+void ubi_free_internal_volumes(struct ubi_device *ubi)
+{
+	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
+}
+
 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
 {
 	int limit, device_pebs;
@@ -1013,7 +1034,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 out_detach:
 	ubi_devices[ubi_num] = NULL;
 	ubi_wl_close(ubi);
-	ubi_free_internal_volumes(ubi);
+	ubi_free_all_volumes(ubi);
 	vfree(ubi->vtbl);
 out_free:
 	vfree(ubi->peb_buf);
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 721b6aa7936c..5ab3affd2fcf 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -948,6 +948,7 @@ int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol,
 int ubi_notify_all(struct ubi_device *ubi, int ntype,
 		   struct notifier_block *nb);
 int ubi_enumerate_volumes(struct notifier_block *nb);
+void ubi_free_all_volumes(struct ubi_device *ubi);
 void ubi_free_internal_volumes(struct ubi_device *ubi);
 
 /* kapi.c */
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index 8a2a0f091598..f700f0e4f2ec 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -782,7 +782,7 @@ static int check_attaching_info(const struct ubi_device *ubi,
  */
 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
 {
-	int i, err;
+	int err;
 	struct ubi_ainf_volume *av;
 
 	empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
@@ -851,13 +851,7 @@ int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
 
 out_free:
 	vfree(ubi->vtbl);
-	for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
-		if (!ubi->volumes[i])
-			continue;
-		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
-		kfree(ubi->volumes[i]);
-		ubi->volumes[i] = NULL;
-	}
+	ubi_free_all_volumes(ubi);
 	return err;
 }
 
-- 
2.22.0




More information about the linux-mtd mailing list