[PATCH 5.10 14/70] firewire: core: extend card->lock in fw_core_handle_bus_reset

Greg Kroah-Hartman
2022-05-10T13:49:18Z

From: Niels Dossche <dossche.niels@gmail.com>

commit a7ecbe92b9243edbe94772f6f2c854e4142a3345 upstream.

card->local_node and card->bm_retries are both always accessed under
card->lock.
fw_core_handle_bus_reset has a check whose condition depends on
card->local_node and whose body writes to card->bm_retries.
Both of these accesses are not under card->lock. Move the lock acquiring
of card->lock to before this check such that these accesses do happen
when card->lock is held.
fw_destroy_nodes is called inside the check.
Since fw_destroy_nodes already acquires card->lock inside its function
body, move this out to the callsites of fw_destroy_nodes.
Also add a comment to indicate which locking is necessary when calling
fw_destroy_nodes.

Cc: <stable@vger.kernel.org>
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220409041243.603210-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/firewire/core-card.c | 3 +++
drivers/firewire/core-topology.c | 9 +++------
2 files changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -668,6 +668,7 @@ EXPORT_SYMBOL_GPL(fw_card_release);
void fw_core_remove_card(struct fw_card *card)
{
struct fw_card_driver dummy_driver = dummy_driver_template;
+ unsigned long flags;

card->driver->update_phy_reg(card, 4,
PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
@@ -682,7 +683,9 @@ void fw_core_remove_card(struct fw_card
dummy_driver.stop_iso = card->driver->stop_iso;
card->driver = &dummy_driver;

+ spin_lock_irqsave(&card->lock, flags);
fw_destroy_nodes(card);
+ spin_unlock_irqrestore(&card->lock, flags);

/* Wait for all users, especially device workqueue jobs, to finish. */
fw_card_put(card);
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -374,16 +374,13 @@ static void report_found_node(struct fw_
card->bm_retries = 0;
}

+/* Must be called with card->lock held */
void fw_destroy_nodes(struct fw_card *card)
{
- unsigned long flags;
-
- spin_lock_irqsave(&card->lock, flags);
card->color++;
if (card->local_node != NULL)
for_each_fw_node(card, card->local_node, report_lost_node);
card->local_node = NULL;
- spin_unlock_irqrestore(&card->lock, flags);
}

static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
@@ -509,6 +506,8 @@ void fw_core_handle_bus_reset(struct fw_
struct fw_node *local_node;
unsigned long flags;

+ spin_lock_irqsave(&card->lock, flags);
+
/*
* If the selfID buffer is not the immediate successor of the
* previously processed one, we cannot reliably compare the
@@ -520,8 +519,6 @@ void fw_core_handle_bus_reset(struct fw_
card->bm_retries = 0;
}

- spin_lock_irqsave(&card->lock, flags);
-
card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
card->node_id = node_id;
/*