From d5dba32b8f6cb39be708b726044ba30dbc088b30 Mon Sep 17 00:00:00 2001
From: Chengfeng Ye <dg573847474@gmail.com>
Date: Thu, 7 Dec 2023 12:34:37 +0000
Subject: [PATCH] atm: solos-pci: Fix potential deadlock on &cli_queue_lock
Git-commit: d5dba32b8f6cb39be708b726044ba30dbc088b30
Patch-mainline: v6.7-rc6
References: git-fixes
As &card->cli_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 #1>
console_show()
--> spin_lock(&card->cli_queue_lock)
<interrupt>
--> solos_bh()
--> spin_lock(&card->cli_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 the card->cli_queue_lock under process context code consistently
to prevent the possible deadlock scenario.
Fixes: 9c54004ea717 ("atm: Driver for Solos PCI ADSL2+ card.")
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 94fbc3abe60e..95f768b28a5e 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -449,9 +449,9 @@ static ssize_t console_show(struct device *dev, struct device_attribute *attr,
struct sk_buff *skb;
unsigned int len;
- spin_lock(&card->cli_queue_lock);
+ spin_lock_bh(&card->cli_queue_lock);
skb = skb_dequeue(&card->cli_queue[SOLOS_CHAN(atmdev)]);
- spin_unlock(&card->cli_queue_lock);
+ spin_unlock_bh(&card->cli_queue_lock);
if(skb == NULL)
return sprintf(buf, "No data.\n");
--
2.35.3