UBI leb_write_unlock NULL pointer Oops (continuation)

[Richard Weinberger]

Am 03.02.2014 13:51, schrieb Wiedemer, Thorsten (Lawo AG):
> Hi,
> 
> I can reproduce it fairly regularly, but not really "quickly". At the moment, I can use a setup of about identical 70 devices.
> A test over the last weekend resultet In 6 devices showing the bug.
> What we have are multiple processes which write in different intervals some data on the device and sync it, because this data should be available after a power cut.
> Perhaps I can force the error more often in writing test processes with shorter write/sync intervals.
> 
> If I have further access to the "big" setup for some days, I will try to make a test without preemption.

Hmm, ok.
Please also apply this patch, just in case...

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 0e11671d..48fd2aa 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -301,6 +301,7 @@ static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)

 	spin_lock(&ubi->ltree_lock);
 	le = ltree_lookup(ubi, vol_id, lnum);
+	ubi_assert(le);
 	le->users -= 1;
 	ubi_assert(le->users >= 0);
 	up_write(&le->mutex);

Thanks,
//richard