firewire: core: fix race with parallel PCI device probe
The config ROM buffer received from generate_config_rom is a globally
shared static buffer. Extend the card_mutex protection in fw_add_card
until after the config ROM was copied into the card driver's buffer.
Otherwise, parallelized card driver probes may end up with ROM contents
that were meant for a different card.
firewire-ohci's card->driver->enable hook is safe to be called within
the card_mutex. Furthermore, it is safe to reorder card_list update
versus card enable, which simplifies the code a little.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index f74edae..e4864e8 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -444,16 +444,13 @@
card->guid = guid;
mutex_lock(&card_mutex);
- config_rom = generate_config_rom(card, &length);
- list_add_tail(&card->link, &card_list);
- mutex_unlock(&card_mutex);
+ config_rom = generate_config_rom(card, &length);
ret = card->driver->enable(card, config_rom, length);
- if (ret < 0) {
- mutex_lock(&card_mutex);
- list_del(&card->link);
- mutex_unlock(&card_mutex);
- }
+ if (ret == 0)
+ list_add_tail(&card->link, &card_list);
+
+ mutex_unlock(&card_mutex);
return ret;
}