Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933646Ab1FWRhr (ORCPT ); Thu, 23 Jun 2011 13:37:47 -0400 Received: from mail.windriver.com ([147.11.1.11]:35148 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933619Ab1FWRhn (ORCPT ); Thu, 23 Jun 2011 13:37:43 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Sean Hefty , Roland Dreier , Paul Gortmaker Subject: [34-longterm 178/247] IB/cm: Bump reference count on cm_id before invoking callback Date: Thu, 23 Jun 2011 13:34:06 -0400 Message-Id: <1308850515-15242-119-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> References: <1308849690-14530-1-git-send-email-paul.gortmaker@windriver.com> <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1984 Lines: 51 From: Sean Hefty ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- commit 29963437a48475036353b95ab142bf199adb909e upstream. When processing a SIDR REQ, the ib_cm allocates a new cm_id. The refcount of the cm_id is initialized to 1. However, cm_process_work will decrement the refcount after invoking all callbacks. The result is that the cm_id will end up with refcount set to 0 by the end of the sidr req handler. If a user tries to destroy the cm_id, the destruction will proceed, under the incorrect assumption that no other threads are referencing the cm_id. This can lead to a crash when the cm callback thread tries to access the cm_id. This problem was noticed as part of a larger investigation with kernel crashes in the rdma_cm when running on a real time OS. Signed-off-by: Sean Hefty Acked-by: Doug Ledford Signed-off-by: Roland Dreier Signed-off-by: Paul Gortmaker --- drivers/infiniband/core/cm.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index ad63b79..2422945 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -2987,6 +2987,7 @@ static int cm_sidr_req_handler(struct cm_work *work) goto out; /* No match. */ } atomic_inc(&cur_cm_id_priv->refcount); + atomic_inc(&cm_id_priv->refcount); spin_unlock_irq(&cm.lock); cm_id_priv->id.cm_handler = cur_cm_id_priv->id.cm_handler; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/