From: Richard Weinberger <richard@xxxxxx>
In some error paths the WL sub-system gives up on a PEB
and frees it's ubi_wl_entry struct but does not set
the entry in ubi->lookuptbl to NULL.
Fastmap can stumble over such a stale pointer as it uses
ubi->lookuptbl to find all PEBs.
Fix this by introducing a new helper function which free()s
a WL entry and removes the reference from the lookup table.
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Conflicts:
drivers/mtd/ubi/wl.c
Fixed minor conflict.
Signed-off-by: Teresa Remmet <t.remmet@xxxxxxxxx>
---
drivers/mtd/ubi/wl.c | 47 +++++++++++++++++++++++++++++++----------------
1 file changed, 31 insertions(+), 16 deletions(-)
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index d168abc..a7ca153 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -194,6 +194,20 @@ static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
rb_insert_color(&e->u.rb, root);
}
+/**
+ * wl_tree_destroy - destroy a wear-leveling entry.
+ * @ubi: UBI device description object
+ * @e: the wear-leveling entry to add
+ *
+ * This function destroys a wear leveling entry and removes
+ * the reference from the lookup table.
+ */
+static void wl_entry_destroy(struct ubi_device *ubi, struct ubi_wl_entry *e)
+{
+ ubi->lookuptbl[e->pnum] = NULL;
+ kfree(e);
+}
+
#ifndef CONFIG_MTD_UBI_FASTMAP
/**
* do_work - do one pending work.
@@ -1182,7 +1196,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
if (err) {
if (e2)
- kfree(e2);
+ wl_entry_destroy(ubi, e2);
goto out_ro;
}
@@ -1244,8 +1258,8 @@ out_error:
ubi->move_to_put = ubi->wl_scheduled = 0;
ubi_free_vid_hdr(ubi, vid_hdr);
- kfree(e1);
- kfree(e2);
+ wl_entry_destroy(ubi, e1);
+ wl_entry_destroy(ubi, e2);
out_ro:
ubi_ro_mode(ubi);
@@ -1375,7 +1389,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
if (shutdown) {
dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
kfree(wl_wrk);
- kfree(e);
+ wl_entry_destroy(ubi, e);
return 0;
}
@@ -1419,7 +1433,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
return err;
}
- kfree(e);
+ wl_entry_destroy(ubi, e);
if (err != -EIO)
/*
* If this is not %-EIO, we have no idea what to do. Scheduling
@@ -1662,9 +1676,10 @@ int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
/**
* tree_destroy - destroy an RB-tree.
+ * @ubi: UBI device description object
* @root: the root of the tree to destroy
*/
-static void tree_destroy(struct rb_root *root)
+static void tree_destroy(struct ubi_device *ubi, struct rb_root *root)
{
struct rb_node *rb;
struct ubi_wl_entry *e;
@@ -1686,7 +1701,7 @@ static void tree_destroy(struct rb_root *root)
rb->rb_right = NULL;
}
- kfree(e);
+ wl_entry_destroy(ubi, e);
}
}
}
@@ -1749,7 +1764,7 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
ubi->lookuptbl[e->pnum] = e;
if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {
- kfree(e);
+ wl_entry_destroy(ubi, e);
goto out_free;
}
@@ -1839,9 +1854,9 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
out_free:
shutdown_work(ubi);
- tree_destroy(&ubi->used);
- tree_destroy(&ubi->free);
- tree_destroy(&ubi->scrub);
+ tree_destroy(ubi, &ubi->used);
+ tree_destroy(ubi, &ubi->free);
+ tree_destroy(ubi, &ubi->scrub);
kfree(ubi->lookuptbl);
return err;
}
@@ -1858,7 +1873,7 @@ static void protection_queue_destroy(struct ubi_device *ubi)
for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
list_del(&e->u.list);
- kfree(e);
+ wl_entry_destroy(ubi, e);
}
}
}
@@ -1889,10 +1904,10 @@ void ubi_wl_close(struct ubi_device *ubi)
ubi_fastmap_close(ubi);
shutdown_work(ubi);
protection_queue_destroy(ubi);
- tree_destroy(&ubi->used);
- tree_destroy(&ubi->erroneous);
- tree_destroy(&ubi->free);
- tree_destroy(&ubi->scrub);
+ tree_destroy(ubi, &ubi->used);
+ tree_destroy(ubi, &ubi->erroneous);
+ tree_destroy(ubi, &ubi->free);
+ tree_destroy(ubi, &ubi->scrub);
kfree(ubi->lookuptbl);
}
--
1.9.1
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