From 3a324606bbabfc30084ce9d08169910773ba9a92 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 16 Dec 2015 18:13:14 +0800 Subject: rhashtable: Enforce minimum size on initial hash table 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 --- lib/rhashtable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 2ff7ed91663a..a98e71db7dd2 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -738,9 +738,6 @@ int rhashtable_init(struct rhashtable *ht, 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); @@ -760,6 +757,9 @@ int rhashtable_init(struct rhashtable *ht, 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 -- cgit v1.2.3