Re: [PATCH] rhashtable: Fix potential deadlock by moving schedule_work outside lock

[Herbert Xu]

On Thu, Nov 28, 2024 at 04:16:25AM -0800, Breno Leitao wrote:
>
> diff --git a/lib/rhashtable.c b/lib/rhashtable.c
> index 6c902639728b767cc3ee42c61256d2e9618e6ce7..5a27ccd72db9a25d92d1ed2f8d519afcfc672afe 100644
> --- a/lib/rhashtable.c
> +++ b/lib/rhashtable.c
> @@ -585,9 +585,6 @@ static struct bucket_table *rhashtable_insert_one(
>  	rht_assign_locked(bkt, obj);
>  
>  	atomic_inc(&ht->nelems);
> -	if (rht_grow_above_75(ht, tbl))
> -		schedule_work(&ht->run_work);
> -
>  	return NULL;
>  }
>  
> @@ -624,6 +621,9 @@ static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
>  				data = ERR_CAST(new_tbl);
>  
>  			rht_unlock(tbl, bkt, flags);
> +			if (rht_grow_above_75(ht, tbl))
> +				schedule_work(&ht->run_work);
> +

The growth check should stay with the atomic_inc.  Something like
this should work:

			if (PTR_ERR(data) == -ENOENT && !new_tbl) {
				atomic_inc(&ht->nelems);
				if (rht_grow_above_75(ht, tbl))
					schedule_work(&ht->run_work);
				break;
			}

Could you please resend this via linux-crypto?

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt