4.2.8-ckt2 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Sebastian Siewior <bigeasy@xxxxxxxxxxxxx>
commit 1a31b20cd81d5cbc7ec6e24cb08066009a1ca32d upstream.
Since fastmap we gained do_sync_erase(). This function can return an error
and its error handling isn't obvious. First the memory allocation for
struct ubi_work can fail and as such struct ubi_wl_entry is leaked.
However if the memory allocation succeeds then the tail function takes
care of the struct ubi_wl_entry. A free here could result in a double
free.
To make the error handling simpler, I split the tail function into one
piece which does the work and another which frees the struct ubi_work
which is passed as argument. As result do_sync_erase() can keep the
struct on stack and we get rid of one error source.
Fixes: 8199b901a ("UBI: Add fastmap support to the WL sub-system")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/mtd/ubi/wl.c | 52 ++++++++++++++++++++++++++++------------------------
1 file changed, 28 insertions(+), 24 deletions(-)
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index eb4489f9..f73233f 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -603,6 +603,7 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
return 0;
}
+static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk);
/**
* do_sync_erase - run the erase worker synchronously.
* @ubi: UBI device description object
@@ -615,20 +616,16 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
int vol_id, int lnum, int torture)
{
- struct ubi_work *wl_wrk;
+ struct ubi_work wl_wrk;
dbg_wl("sync erase of PEB %i", e->pnum);
- wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
- if (!wl_wrk)
- return -ENOMEM;
-
- wl_wrk->e = e;
- wl_wrk->vol_id = vol_id;
- wl_wrk->lnum = lnum;
- wl_wrk->torture = torture;
+ wl_wrk.e = e;
+ wl_wrk.vol_id = vol_id;
+ wl_wrk.lnum = lnum;
+ wl_wrk.torture = torture;
- return erase_worker(ubi, wl_wrk, 0);
+ return __erase_worker(ubi, &wl_wrk);
}
/**
@@ -1014,7 +1011,7 @@ out_unlock:
}
/**
- * erase_worker - physical eraseblock erase worker function.
+ * __erase_worker - physical eraseblock erase worker function.
* @ubi: UBI device description object
* @wl_wrk: the work object
* @shutdown: non-zero if the worker has to free memory and exit
@@ -1025,8 +1022,7 @@ out_unlock:
* needed. Returns zero in case of success and a negative error code in case of
* failure.
*/
-static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
- int shutdown)
+static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk)
{
struct ubi_wl_entry *e = wl_wrk->e;
int pnum = e->pnum;
@@ -1034,21 +1030,11 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
int lnum = wl_wrk->lnum;
int err, available_consumed = 0;
- if (shutdown) {
- dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
- kfree(wl_wrk);
- wl_entry_destroy(ubi, e);
- return 0;
- }
-
dbg_wl("erase PEB %d EC %d LEB %d:%d",
pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
err = sync_erase(ubi, e, wl_wrk->torture);
if (!err) {
- /* Fine, we've erased it successfully */
- kfree(wl_wrk);
-
spin_lock(&ubi->wl_lock);
wl_tree_add(e, &ubi->free);
ubi->free_count++;
@@ -1066,7 +1052,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
}
ubi_err(ubi, "failed to erase PEB %d, error %d", pnum, err);
- kfree(wl_wrk);
if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
err == -EBUSY) {
@@ -1150,6 +1135,25 @@ out_ro:
return err;
}
+static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
+ int shutdown)
+{
+ int ret;
+
+ if (shutdown) {
+ struct ubi_wl_entry *e = wl_wrk->e;
+
+ dbg_wl("cancel erasure of PEB %d EC %d", e->pnum, e->ec);
+ kfree(wl_wrk);
+ wl_entry_destroy(ubi, e);
+ return 0;
+ }
+
+ ret = __erase_worker(ubi, wl_wrk);
+ kfree(wl_wrk);
+ return ret;
+}
+
/**
* ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
* @ubi: UBI device description object
--
1.9.1
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