staging: lustre: take extra refcount in kiblnd_connreq_done (992f0b22) · Commits · 戴 / test

refcount taken by cmid is not reliable after kiblnd_connreq_done released the glock because this connection is visible to other threads, another thread can find and close this connection right after kiblnd_connreq_done released the glock, if kiblnd_cm_callback for RDMA_CM_EVENT_DISCONNECTED is called, it can release the connection refcount taken by cmid. It means the connection could be destroyed before kiblnd_connreq_done() finish operations on it. Signed-off-by:

Liang Zhen <liang.zhen@intel.com> ntel-bug-id: https://jira.hpdd.intel.com/browse/LU-7210 Reviewed-on: http://review.whamcloud.com/17527 Reviewed-by:

Doug Oucharek <doug.s.oucharek@intel.com> Reviewed-by:

James Simmons <uja.ornl@yahoo.com> Tested-by:

James Simmons <uja.ornl@yahoo.com> Reviewed-by:

Oleg Drokin <oleg.drokin@intel.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -939,8 +939,6 @@ kiblnd_check_sends(kib_conn_t *conn)
		kiblnd_queue_tx_locked(tx, conn);
		}

		kiblnd_conn_addref(conn); /* 1 ref for me.... (see b21911) */

		for (;;) {
		int credit;

		@@ -966,8 +964,6 @@ kiblnd_check_sends(kib_conn_t *conn)
		}

		spin_unlock(&conn->ibc_lock);

		kiblnd_conn_decref(conn); /* ...until here */
		}

		static void
		@@ -2131,6 +2127,16 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)
		return;
		}

		/**
		* refcount taken by cmid is not reliable after I released the glock
		* because this connection is visible to other threads now, another
		* thread can find and close this connection right after I released
		* the glock, if kiblnd_cm_callback for RDMA_CM_EVENT_DISCONNECTED is
		* called, it can release the connection refcount taken by cmid.
		* It means the connection could be destroyed before I finish my
		* operations on it.
		*/
		kiblnd_conn_addref(conn);
		write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

		/* Schedule blocked txs */
		@@ -2146,6 +2152,8 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)

		/* schedule blocked rxs */
		kiblnd_handle_early_rxs(conn);

		kiblnd_conn_decref(conn);
		}

		static void

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