2022-11-23 10:31:33

by Duoming Zhou

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

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 <[email protected]>
---
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

2022-11-25 08:40:23

by patchwork-bot+netdevbpf

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

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

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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