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* [bug report] thermal/debugfs: Add thermal cooling device debugfs information
@ 2024-01-12  8:13 Dan Carpenter
  2024-01-12 14:50 ` Rafael J. Wysocki
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2024-01-12  8:13 UTC (permalink / raw)
  To: daniel.lezcano; +Cc: linux-pm

Hello Daniel Lezcano,

The patch 90f2fb4afe8b: "thermal/debugfs: Add thermal cooling device
debugfs information" from Jan 9, 2024 (linux-next), leads to the
following Smatch static checker warning:

drivers/thermal/thermal_debugfs.c:517 thermal_debug_cdev_remove() warn: 'thermal_dbg' was already freed. (line 515)
drivers/thermal/thermal_debugfs.c:835 thermal_debug_tz_remove() warn: 'thermal_dbg' was already freed. (line 833)

drivers/thermal/thermal_debugfs.c
    504 void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
    505 {
    506         struct thermal_debugfs *thermal_dbg = cdev->debugfs;
    507 
    508         if (!thermal_dbg)
    509                 return;
    510 
    511         mutex_lock(&thermal_dbg->lock);
    512 
    513         thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
    514         cdev->debugfs = NULL;
    515         thermal_debugfs_remove_id(thermal_dbg);
                                          ^^^^^^^^^^^
Freed here.

    516 
--> 517         mutex_unlock(&thermal_dbg->lock);
                             ^^^^^^^^^^^^^^^^^^
Use after free.  Same issue in the tz remove() function.

    518 }

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [bug report] thermal/debugfs: Add thermal cooling device debugfs information
  2024-01-12  8:13 [bug report] thermal/debugfs: Add thermal cooling device debugfs information Dan Carpenter
@ 2024-01-12 14:50 ` Rafael J. Wysocki
  0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2024-01-12 14:50 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: daniel.lezcano, linux-pm

On Fri, Jan 12, 2024 at 9:13 AM Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> Hello Daniel Lezcano,
>
> The patch 90f2fb4afe8b: "thermal/debugfs: Add thermal cooling device
> debugfs information" from Jan 9, 2024 (linux-next), leads to the
> following Smatch static checker warning:
>
> drivers/thermal/thermal_debugfs.c:517 thermal_debug_cdev_remove() warn: 'thermal_dbg' was already freed. (line 515)
> drivers/thermal/thermal_debugfs.c:835 thermal_debug_tz_remove() warn: 'thermal_dbg' was already freed. (line 833)
>
> drivers/thermal/thermal_debugfs.c
>     504 void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
>     505 {
>     506         struct thermal_debugfs *thermal_dbg = cdev->debugfs;
>     507
>     508         if (!thermal_dbg)
>     509                 return;
>     510
>     511         mutex_lock(&thermal_dbg->lock);
>     512
>     513         thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
>     514         cdev->debugfs = NULL;
>     515         thermal_debugfs_remove_id(thermal_dbg);
>                                           ^^^^^^^^^^^
> Freed here.
>
>     516
> --> 517         mutex_unlock(&thermal_dbg->lock);
>                              ^^^^^^^^^^^^^^^^^^
> Use after free.  Same issue in the tz remove() function.
>
>     518 }
>

Good catch, thanks!

Fixed up in the tree.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2024-01-12  8:13 [bug report] thermal/debugfs: Add thermal cooling device debugfs information Dan Carpenter
2024-01-12 14:50 ` Rafael J. Wysocki

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