diff mbox series

hwmon: (xgene) Fix use after free bug in xgene_hwmon_remove due to race condition

Message ID 20230310084007.1403388-1-zyytlz.wz@163.com
State New
Headers
Series hwmon: (xgene) Fix use after free bug in xgene_hwmon_remove due to race condition |

Commit Message

Zheng Wang March 10, 2023, 8:40 a.m. UTC 
  In xgene_hwmon_probe, &ctx->workq is bound with
xgene_hwmon_evt_work. Then it will be started.

If we remove the driver which will call
xgene_hwmon_remove to make cleanup, there may
be a unfinished work.

The possiblesequence is as follows:

Fix it by finishing the work before cleanup in the
xgene_hwmon_remove

CPU0                  CPU1

                    |xgene_hwmon_evt_work
xgene_hwmon_remove   |
kfifo_free(&ctx->async_msg_fifo);|
                    |
                    |kfifo_out_spinlocked
                    |//use &ctx->async_msg_fifo
Fixes: 2ca492e22cb7 ("hwmon: (xgene) Fix crash when alarm occurs before driver probe")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
 drivers/hwmon/xgene-hwmon.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Guenter Roeck March 10, 2023, 4:34 p.m. UTC | #1 
On Fri, Mar 10, 2023 at 04:40:07PM +0800, Zheng Wang wrote:
> In xgene_hwmon_probe, &ctx->workq is bound with
> xgene_hwmon_evt_work. Then it will be started.
> 
> If we remove the driver which will call
> xgene_hwmon_remove to make cleanup, there may
> be a unfinished work.
> 
> The possiblesequence is as follows:
> 
> Fix it by finishing the work before cleanup in the
> xgene_hwmon_remove
> 
> CPU0                  CPU1
> 
>                     |xgene_hwmon_evt_work
> xgene_hwmon_remove   |
> kfifo_free(&ctx->async_msg_fifo);|
>                     |
>                     |kfifo_out_spinlocked
>                     |//use &ctx->async_msg_fifo
> Fixes: 2ca492e22cb7 ("hwmon: (xgene) Fix crash when alarm occurs before driver probe")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/xgene-hwmon.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
> index 5cde837bfd09..d1abea49f01b 100644
> --- a/drivers/hwmon/xgene-hwmon.c
> +++ b/drivers/hwmon/xgene-hwmon.c
> @@ -761,6 +761,7 @@ static int xgene_hwmon_remove(struct platform_device *pdev)
>  {
>  	struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
>  
> +	cancel_work_sync(&ctx->workq);
>  	hwmon_device_unregister(ctx->hwmon_dev);
>  	kfifo_free(&ctx->async_msg_fifo);
>  	if (acpi_disabled)
Zheng Hacker March 10, 2023, 4:54 p.m. UTC | #2 
Guenter Roeck <linux@roeck-us.net> 于2023年3月11日周六 00:34写道：
>
> On Fri, Mar 10, 2023 at 04:40:07PM +0800, Zheng Wang wrote:
> > In xgene_hwmon_probe, &ctx->workq is bound with
> > xgene_hwmon_evt_work. Then it will be started.
> >
> > If we remove the driver which will call
> > xgene_hwmon_remove to make cleanup, there may
> > be a unfinished work.
> >
> > The possiblesequence is as follows:
> >
> > Fix it by finishing the work before cleanup in the
> > xgene_hwmon_remove
> >
> > CPU0                  CPU1
> >
> >                     |xgene_hwmon_evt_work
> > xgene_hwmon_remove   |
> > kfifo_free(&ctx->async_msg_fifo);|
> >                     |
> >                     |kfifo_out_spinlocked
> >                     |//use &ctx->async_msg_fifo
> > Fixes: 2ca492e22cb7 ("hwmon: (xgene) Fix crash when alarm occurs before driver probe")
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
>
> Applied.
>
Thanks for your effort.

Best regards,
Zheng
>
> > ---
> >  drivers/hwmon/xgene-hwmon.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
> > index 5cde837bfd09..d1abea49f01b 100644
> > --- a/drivers/hwmon/xgene-hwmon.c
> > +++ b/drivers/hwmon/xgene-hwmon.c
> > @@ -761,6 +761,7 @@ static int xgene_hwmon_remove(struct platform_device *pdev)
> >  {
> >       struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
> >
> > +     cancel_work_sync(&ctx->workq);
> >       hwmon_device_unregister(ctx->hwmon_dev);
> >       kfifo_free(&ctx->async_msg_fifo);
> >       if (acpi_disabled)
diff mbox series

Patch

diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
index 5cde837bfd09..d1abea49f01b 100644
--- a/drivers/hwmon/xgene-hwmon.c
+++ b/drivers/hwmon/xgene-hwmon.c
@@ -761,6 +761,7 @@  static int xgene_hwmon_remove(struct platform_device *pdev)
 {
 	struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
 
+	cancel_work_sync(&ctx->workq);
 	hwmon_device_unregister(ctx->hwmon_dev);
 	kfifo_free(&ctx->async_msg_fifo);
 	if (acpi_disabled)