This is a note to let you know that I've just added the patch titled rhashtable: Enforce minimum size on initial hash table to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rhashtable-enforce-minimum-size-on-initial-hash-table.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Dec 30 19:52:45 PST 2015 From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Date: Wed, 16 Dec 2015 18:13:14 +0800 Subject: rhashtable: Enforce minimum size on initial hash table From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> [ Upstream commit 3a324606bbabfc30084ce9d08169910773ba9a92 ] William Hua <william.hua@xxxxxxxxxxxxx> 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 <william.hua@xxxxxxxxxxxxx> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/rhashtable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -730,9 +730,6 @@ 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); @@ -752,6 +749,9 @@ 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 Patches currently in stable-queue which might be from herbert@xxxxxxxxxxxxxxxxxxx are queue-4.1/rhashtable-fix-walker-list-corruption.patch queue-4.1/rhashtable-enforce-minimum-size-on-initial-hash-table.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html