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UBI: fix use-after-free on error path

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When we fail to erase a PEB, we free the corresponding erase entry object,
but then re-schedule this object if the error code was something like -EAGAIN.
Obviously, it is a bug to use the object after we have freed it.

Reported-by: Emese Revfy <re.emese@gmail.com>
Cc: stable@kernel.org [v2.6.23+]
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
This commit is contained in:
Artem Bityutskiy 2012-01-05 10:47:18 +02:00
parent e801e128b2
commit e57e0d8e81
1 changed files with 4 additions and 3 deletions
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7
drivers/mtd/ubi/wl.c
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@ -1052,7 +1052,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
ubi_err("failed to erase PEB %d, error %d", pnum, err);
kfree(wl_wrk);
kmem_cache_free(ubi_wl_entry_slab, e);
if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
err == -EBUSY) {
@ -1065,14 +1064,16 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
goto out_ro;
}
return err;
} else if (err != -EIO) {
}
kmem_cache_free(ubi_wl_entry_slab, e);
if (err != -EIO)
/*
* If this is not %-EIO, we have no idea what to do. Scheduling
* this physical eraseblock for erasure again would cause
* errors again and again. Well, lets switch to R/O mode.
*/
goto out_ro;
}
/* It is %-EIO, the PEB went bad */