Commit b171e204 authored Sep 06, 2009 by Stefan Richter

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>

parent 18668ff9

drivers/firewire/core-card.c

+5 −8

Original line number	Diff line number	Diff line
		@@ -444,16 +444,13 @@ int fw_card_add(struct fw_card *card,
		card->guid = guid;

		mutex_lock(&card_mutex);

		config_rom = generate_config_rom(card, &length);
		ret = card->driver->enable(card, config_rom, length);
		if (ret == 0)
		list_add_tail(&card->link, &card_list);
		mutex_unlock(&card_mutex);

		ret = card->driver->enable(card, config_rom, length);
		if (ret < 0) {
		mutex_lock(&card_mutex);
		list_del(&card->link);
		mutex_unlock(&card_mutex);
		}

		return ret;
		}