[PATCH net] qlcnic: fix sleep-in-atomic-context bugs caused by msleep

[PATCH net] qlcnic: fix sleep-in-atomic-context bugs caused by msleep

[Duoming Zhou]

The watchdog timer is used to monitor whether the process
of transmitting data is timeout. If we use qlcnic driver,
the dev_watchdog() that is the timer handler of watchdog
timer will call qlcnic_tx_timeout() to process the timeout.
But the qlcnic_tx_timeout() calls msleep(), as a result,
the sleep-in-atomic-context bugs will happen. The processes
are shown below:

   (atomic context)
dev_watchdog
  qlcnic_tx_timeout
    qlcnic_83xx_idc_request_reset
      qlcnic_83xx_lock_driver
        msleep

---------------------------

   (atomic context)
dev_watchdog
  qlcnic_tx_timeout
    qlcnic_83xx_idc_request_reset
      qlcnic_83xx_lock_driver
        qlcnic_83xx_recover_driver_lock
          msleep

Fix by changing msleep() to mdelay(), the mdelay() is
busy-waiting and the bugs could be mitigated.

Fixes: 629263acaea3 ("qlcnic: 83xx CNA inter driver communication mechanism")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
index bd060768032..2fd5c6fdb50 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
@@ -2991,7 +2991,7 @@ static void qlcnic_83xx_recover_driver_lock(struct qlcnic_adapter *adapter)
 		QLCWRX(adapter->ahw, QLC_83XX_RECOVER_DRV_LOCK, val);
 		dev_info(&adapter->pdev->dev,
 			 "%s: lock recovery initiated\n", __func__);
-		msleep(QLC_83XX_DRV_LOCK_RECOVERY_DELAY);
+		mdelay(QLC_83XX_DRV_LOCK_RECOVERY_DELAY);
 		val = QLCRDX(adapter->ahw, QLC_83XX_RECOVER_DRV_LOCK);
 		id = ((val >> 2) & 0xF);
 		if (id == adapter->portnum) {
@@ -3027,7 +3027,7 @@ int qlcnic_83xx_lock_driver(struct qlcnic_adapter *adapter)
 		if (status)
 			break;
 
-		msleep(QLC_83XX_DRV_LOCK_WAIT_DELAY);
+		mdelay(QLC_83XX_DRV_LOCK_WAIT_DELAY);
 		i++;
 
 		if (i == 1)
-- 
2.17.1

Re: [PATCH net] qlcnic: fix sleep-in-atomic-context bugs caused by msleep

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Wed, 23 Nov 2022 18:06:42 +0800 you wrote:
> The watchdog timer is used to monitor whether the process
> of transmitting data is timeout. If we use qlcnic driver,
> the dev_watchdog() that is the timer handler of watchdog
> timer will call qlcnic_tx_timeout() to process the timeout.
> But the qlcnic_tx_timeout() calls msleep(), as a result,
> the sleep-in-atomic-context bugs will happen. The processes
> are shown below:
> 
> [...]

Here is the summary with links:
  - [net] qlcnic: fix sleep-in-atomic-context bugs caused by msleep
    https://git.kernel.org/netdev/net/c/8dbd6e4ce1b9

You are awesome, thank you!
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