This is a note to let you know that I've just added the patch titled
IB/cm: Bump reference count on cm_id before invoking callback
to the 2.6.32-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.32.git;a=summary
The filename of the patch is:
ib-cm-bump-reference-count-on-cm_id-before-invoking-callback.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.32 longterm
tree,
please let <[email protected]> know about it.
>From 29963437a48475036353b95ab142bf199adb909e Mon Sep 17 00:00:00 2001
From: Sean Hefty <[email protected]>
Date: Wed, 23 Feb 2011 08:17:40 -0800
Subject: IB/cm: Bump reference count on cm_id before invoking callback
From: Sean Hefty <[email protected]>
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 <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Signed-off-by: Roland Dreier <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/infiniband/core/cm.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -2986,6 +2986,7 @@ static int cm_sidr_req_handler(struct cm
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;
Patches currently in longterm-queue-2.6.32 which might be from
[email protected] are
/home/gregkh/linux/longterm/longterm-queue-2.6.32/queue-2.6.32/rdma-cma-fix-crash-in-request-handlers.patch
/home/gregkh/linux/longterm/longterm-queue-2.6.32/queue-2.6.32/ib-cm-bump-reference-count-on-cm_id-before-invoking-callback.patch
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