Re: [rhashtable] [ INFO: possible recursive locking detected ]

From: Herbert Xu
Date: Wed Mar 11 2015 - 23:47:26 EST


On Wed, Mar 11, 2015 at 11:41:56PM -0400, David Miller wrote:
> From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Date: Thu, 12 Mar 2015 14:37:45 +1100
>
> > rhashtable: Add annotation to nested lock
> >
> > Commit aa34a6cb0478842452bac58edb50d3ef9e178c92 ("rhashtable:
> > Add arbitrary rehash function") killed the annotation on the
> > nested lock which leads to bitching from lockdep.
> >
> > Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> > Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>
> This doesn't apply to net-next, the second hunk gives a reject.

Sorry, I based on this on top of the cleanup patches sent earlier.
Here is a rebase on net-next. I will resend the cleanups later.

--8<--
rhashtable: Add annotation to nested lock

Commit aa34a6cb0478842452bac58edb50d3ef9e178c92 ("rhashtable:
Add arbitrary rehash function") killed the annotation on the
nested lock which leads to bitching from lockdep.

Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index b1c19c5..d7f3db5 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -234,7 +234,7 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned old_hash)

new_bucket_lock = bucket_lock(new_tbl, new_hash);

- spin_lock(new_bucket_lock);
+ spin_lock_nested(new_bucket_lock, RHT_LOCK_NESTED);
head = rht_dereference_bucket(new_tbl->buckets[new_hash],
new_tbl, new_hash);

@@ -415,7 +415,7 @@ static bool __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
tbl = rht_dereference_rcu(ht->future_tbl, ht);
if (tbl != old_tbl) {
hash = obj_raw_hashfn(ht, tbl, rht_obj(ht, obj));
- spin_lock(bucket_lock(tbl, hash));
+ spin_lock_nested(bucket_lock(tbl, hash), RHT_LOCK_NESTED);
}

if (compare &&

--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/