2008-03-04 22:45:15

by Steve Wise

Subject: [PATCH 2.6.25] RDMA/IWCM: don't access the cm_id after dereferencing it.

RDMA/IWCM: don't access the cm_id after dereferencing it.

cm_work_handler() can access cm_id_priv after it was potentially freed
by iwch_deref_id(). The fix is to note whether IWCM_F_CALLBACK_DESTROY
is set before dereferencing. Then if it was set, free the cm_id on
this thread.

Signed-off-by: Steve Wise <[email protected]>
---

drivers/infiniband/core/iwcm.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index 223b1aa..81c9195 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -839,6 +839,7 @@ static void cm_work_handler(struct work_struct *_work)
unsigned long flags;
int empty;
int ret = 0;
+ int destroy_id;

spin_lock_irqsave(&cm_id_priv->lock, flags);
empty = list_empty(&cm_id_priv->work_list);
@@ -857,9 +858,9 @@ static void cm_work_handler(struct work_struct *_work)
destroy_cm_id(&cm_id_priv->id);
}
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
+ destroy_id = test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
if (iwcm_deref_id(cm_id_priv)) {
- if (test_bit(IWCM_F_CALLBACK_DESTROY,
- &cm_id_priv->flags)) {
+ if (destroy_id) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}

2008-03-11 04:33:19

by Roland Dreier

Subject: Re: [PATCH 2.6.25] RDMA/IWCM: don't access the cm_id after dereferencing it.

thanks, applied.