From e47e321a35c741ee41b67976f8c6a3a7a42bc5c0 Mon Sep 17 00:00:00 2001 From: Bernd Schubert Date: Fri, 20 Jan 2012 18:43:54 +0000 Subject: [PATCH] RDMA/core: Fix kernel panic by always initializing qp->usecnt We have just been investigating kernel panics related to cq->ibcq.event_handler() completion calls. The problem is that ib_destroy_qp() fails with -EBUSY. Further investigation revealed qp->usecnt is not initialized. This counter was introduced in linux-3.2 by commit 0e0ec7e0638e ("RDMA/core: Export ib_open_qp() to share XRC TGT QPs") but it only gets initialized for IB_QPT_XRC_TGT, but it is checked in ib_destroy_qp() for any QP type. Fix this by initializing qp->usecnt for every QP we create. Signed-off-by: Bernd Schubert Signed-off-by: Sven Breuner [ Initialize qp->usecnt in uverbs too. - Sean ] Signed-off-by: Sean Hefty Cc: Signed-off-by: Roland Dreier --- drivers/infiniband/core/uverbs_cmd.c | 1 + drivers/infiniband/core/verbs.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index b930da4c0c63..4d27e4c3fe34 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -1485,6 +1485,7 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file, qp->event_handler = attr.event_handler; qp->qp_context = attr.qp_context; qp->qp_type = attr.qp_type; + atomic_set(&qp->usecnt, 0); atomic_inc(&pd->usecnt); atomic_inc(&attr.send_cq->usecnt); if (attr.recv_cq) diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c index 602b1bd723a9..575b78045aaf 100644 --- a/drivers/infiniband/core/verbs.c +++ b/drivers/infiniband/core/verbs.c @@ -421,6 +421,7 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd, qp->uobject = NULL; qp->qp_type = qp_init_attr->qp_type; + atomic_set(&qp->usecnt, 0); if (qp_init_attr->qp_type == IB_QPT_XRC_TGT) { qp->event_handler = __ib_shared_qp_event_handler; qp->qp_context = qp; @@ -430,7 +431,6 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd, qp->xrcd = qp_init_attr->xrcd; atomic_inc(&qp_init_attr->xrcd->usecnt); INIT_LIST_HEAD(&qp->open_list); - atomic_set(&qp->usecnt, 0); real_qp = qp; qp = __ib_open_qp(real_qp, qp_init_attr->event_handler,