5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chengfeng Ye dg573847474@gmail.com
[ Upstream commit 15319a4e8ee4b098118591c6ccbd17237f841613 ]
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: 213e85d38912 ("solos-pci: clean up pclose() function") Signed-off-by: Chengfeng Ye dg573847474@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/atm/solos-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c index f7ec9ef361921..9f2148daf8ad1 100644 --- a/drivers/atm/solos-pci.c +++ b/drivers/atm/solos-pci.c @@ -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) {