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atm: solos-pci: Fix potential deadlock on &tx_queue_lock

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As &card->tx_queue_lock is acquired under softirq context along the
following call chain from solos_bh(), other acquisition of the same
lock inside process context should disable at least bh to avoid double
lock.

<deadlock #2>
pclose()
--> spin_lock(&card->tx_queue_lock)
<interrupt>
   --> solos_bh()
   --> fpga_tx()
   --> spin_lock(&card->tx_queue_lock)

This flaw was found by an experimental static analysis tool I am
developing for irq-related deadlock.

To prevent the potential deadlock, the patch uses spin_lock_bh()
on &card->tx_queue_lock under process context code consistently to
prevent the possible deadlock scenario.

Fixes: 213e85d389 ("solos-pci: clean up pclose() function")
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chengfeng Ye 2023-12-07 12:34:53 +00:00 committed by David S. Miller
parent d5dba32b8f
commit 15319a4e8e
1 changed files with 2 additions and 2 deletions
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4
drivers/atm/solos-pci.c
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@ -956,14 +956,14 @@ static void pclose(struct atm_vcc *vcc)
struct pkt_hdr *header;
/* Remove any yet-to-be-transmitted packets from the pending queue */
spin_lock(&card->tx_queue_lock);
spin_lock_bh(&card->tx_queue_lock);
skb_queue_walk_safe(&card->tx_queue[port], skb, tmpskb) {
if (SKB_CB(skb)->vcc == vcc) {
skb_unlink(skb, &card->tx_queue[port]);
solos_pop(vcc, skb);
}
}
spin_unlock(&card->tx_queue_lock);
spin_unlock_bh(&card->tx_queue_lock);
skb = alloc_skb(sizeof(*header), GFP_KERNEL);
if (!skb) {