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Subject[PATCH 4/6] 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>
---
drivers/firewire/core-card.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

Index: linux-2.6.31-rc9/drivers/firewire/core-card.c
===================================================================
--- linux-2.6.31-rc9.orig/drivers/firewire/core-card.c
+++ linux-2.6.31-rc9/drivers/firewire/core-card.c
@@ -449,16 +449,13 @@ int fw_card_add(struct fw_card *card,
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;
}
--
Stefan Richter
-=====-==--= =--= --==-
http://arcgraph.de/sr/


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