From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yipeng Wang Subject: [PATCH v4 2/8] hash: fix a multi-writer race condition Date: Mon, 9 Jul 2018 03:44:57 -0700 Message-ID: <1531133103-437316-3-git-send-email-yipeng1.wang@intel.com> References: <1528455078-328182-1-git-send-email-yipeng1.wang@intel.com> <1531133103-437316-1-git-send-email-yipeng1.wang@intel.com> Cc: dev@dpdk.org, yipeng1.wang@intel.com, bruce.richardson@intel.com, honnappa.nagarahalli@arm.com, vguvva@caviumnetworks.com, brijesh.s.singh@gmail.com To: pablo.de.lara.guarch@intel.com Return-path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id DA7C2324B for ; Mon, 9 Jul 2018 19:52:23 +0200 (CEST) In-Reply-To: <1531133103-437316-1-git-send-email-yipeng1.wang@intel.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Current multi-writer implementation uses Intel TSX to protect the cuckoo path moving but not the cuckoo path searching. After searching, we need to verify again if the same empty slot still exists at the begining of the TSX region. Otherwise another writer could occupy the empty slot before the TSX region. Current code does not verify. Fixes: be856325cba3 ("hash: add scalable multi-writer insertion with Intel TSX") Cc: stable@dpdk.org Signed-off-by: Yipeng Wang Acked-by: Pablo de Lara --- lib/librte_hash/rte_cuckoo_hash_x86.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/librte_hash/rte_cuckoo_hash_x86.h b/lib/librte_hash/rte_cuckoo_hash_x86.h index 2c5b017..981d7bd 100644 --- a/lib/librte_hash/rte_cuckoo_hash_x86.h +++ b/lib/librte_hash/rte_cuckoo_hash_x86.h @@ -66,6 +66,9 @@ rte_hash_cuckoo_move_insert_mw_tm(const struct rte_hash *h, while (try < RTE_HASH_TSX_MAX_RETRY) { status = rte_xbegin(); if (likely(status == RTE_XBEGIN_STARTED)) { + /* In case empty slot was gone before entering TSX */ + if (curr_bkt->key_idx[curr_slot] != EMPTY_SLOT) + rte_xabort(RTE_XABORT_CUCKOO_PATH_INVALIDED); while (likely(curr_node->prev != NULL)) { prev_node = curr_node->prev; prev_bkt = prev_node->bkt; -- 2.7.4