From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, William Hua , Herbert Xu , "David S. Miller" Subject: [PATCH 4.3 48/55] rhashtable: Enforce minimum size on initial hash table Date: Wed, 20 Jan 2016 16:44:23 -0800 Message-Id: <20160120232229.873250381@linuxfoundation.org> In-Reply-To: <20160120232227.417513468@linuxfoundation.org> References: <20160120232227.417513468@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu [ Upstream commit 3a324606bbabfc30084ce9d08169910773ba9a92 ] William Hua wrote: > > I wasn't aware there was an enforced minimum size. I simply set the > nelem_hint in the rhastable_params struct to 1, expecting it to grow as > needed. This caused a segfault afterwards when trying to insert an > element. OK we're doing the size computation before we enforce the limit on min_size. ---8<--- We need to do the initial hash table size computation after we have obtained the correct min_size/max_size parameters. Otherwise we may end up with a hash table whose size is outside the allowed envelope. Fixes: a998f712f77e ("rhashtable: Round up/down min/max_size to...") Reported-by: William Hua Signed-off-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- lib/rhashtable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -723,9 +723,6 @@ int rhashtable_init(struct rhashtable *h if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT)) return -EINVAL; - if (params->nelem_hint) - size = rounded_hashtable_size(params); - memset(ht, 0, sizeof(*ht)); mutex_init(&ht->mutex); spin_lock_init(&ht->lock); @@ -745,6 +742,9 @@ int rhashtable_init(struct rhashtable *h ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE); + if (params->nelem_hint) + size = rounded_hashtable_size(&ht->p); + /* The maximum (not average) chain length grows with the * size of the hash table, at a rate of (log N)/(log log N). * The value of 16 is selected so that even if the hash