From a5c7f4710fba334bf613d705f97b4471b36446f8 Mon Sep 17 00:00:00 2001
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
Date: Wed, 19 Mar 2008 22:02:40 +0100
Subject: [PATCH] firewire: insist on successive self ID complete events
The whole topology code only works if the old and new topologies which
are compared come from immediately successive self ID complete events.
If there happened bus resets without self ID complete events in the
meantime, or self ID complete events with invalid selfIDs, the topology
comparison could identify nodes wrongly, or more likely just corrupt
kernel memory or panic right away.
We now discard all nodes of the old topology and treat all current nodes
as new ones if the current self ID generation is not the previous one
plus 1.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
---
drivers/firewire/fw-topology.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c
index c9be6e6948c4..e7520e4bd6bc 100644
--- a/drivers/firewire/fw-topology.c
+++ b/drivers/firewire/fw-topology.c
@@ -518,6 +518,18 @@ fw_core_handle_bus_reset(struct fw_card *card,
struct fw_node *local_node;
unsigned long flags;
+ /*
+ * If the selfID buffer is not the immediate successor of the
+ * previously processed one, we cannot reliably compare the
+ * old and new topologies.
+ */
+ if ((generation & 0xff) != ((card->generation + 1) & 0xff) &&
+ card->local_node != NULL) {
+ fw_notify("skipped bus generations, destroying all nodes\n");
+ fw_destroy_nodes(card);
+ card->bm_retries = 0;
+ }
+
spin_lock_irqsave(&card->lock, flags);
card->node_id = node_id;
--
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