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From: Reto Schneider <code@reto-schneider.ch>
To: linux-wireless@vger.kernel.org
Cc: Larry.Finger@lwfinger.net, Reto Schneider <code@reto-schneider.ch>
Subject: [PATCH 1/3] rtl8192cu: Fix deadlock
Date: Mon, 22 Jun 2020 15:21:11 +0200	[thread overview]
Message-ID: <20200622132113.14508-2-code@reto-schneider.ch> (raw)
In-Reply-To: <20200622132113.14508-1-code@reto-schneider.ch>

Prevent code from calling itself indirectly, causing the driver to hang
and consume 100% CPU.

Without this fix, the following script can bring down a single CPU
system:
```
while true; do
  rmmod rtl8192cu
  modprobe rtl8192cu
done
```

Signed-off-by: Reto Schneider <code@reto-schneider.ch>
---
 drivers/net/wireless/realtek/rtlwifi/usb.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/usb.c b/drivers/net/wireless/realtek/rtlwifi/usb.c
index c66c6dc00378..d3bbfc0171f6 100644
--- a/drivers/net/wireless/realtek/rtlwifi/usb.c
+++ b/drivers/net/wireless/realtek/rtlwifi/usb.c
@@ -680,8 +680,10 @@ static void _rtl_usb_cleanup_rx(struct ieee80211_hw *hw)
 	tasklet_kill(&rtlusb->rx_work_tasklet);
 	cancel_work_sync(&rtlpriv->works.lps_change_work);
 
-	flush_workqueue(rtlpriv->works.rtl_wq);
-	destroy_workqueue(rtlpriv->works.rtl_wq);
+	if (rtlpriv->works.rtl_wq) {
+		destroy_workqueue(rtlpriv->works.rtl_wq);
+		rtlpriv->works.rtl_wq = NULL;
+	}
 
 	skb_queue_purge(&rtlusb->rx_queue);
 
-- 
2.20.1


  reply	other threads:[~2020-06-22 13:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-22 13:21 [PATCH 0/3] rtl8192cu: Fixes for leaks and deadlock Reto Schneider
2020-06-22 13:21 ` Reto Schneider [this message]
2020-06-22 18:01   ` [PATCH 1/3] rtl8192cu: Fix deadlock Larry Finger
2020-06-23  9:20     ` Kalle Valo
2020-07-15 10:37   ` [PATCH 1/3] rtlwifi: " Kalle Valo
2020-06-22 13:21 ` [PATCH 2/3] rtl8192cu: Prevent leaking urb Reto Schneider
2020-06-22 13:21 ` [PATCH 3/3] rtl8192cu: Free ieee80211_hw if probing fails Reto Schneider

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