From: Ashutosh Dixit <ashutosh.dixit@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: "Badal Nilawar" <badal.nilawar@intel.com>,
"Andi Shyti" <andi.shyti@intel.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
linux-hwmon@vger.kernel.org
Subject: [PATCH] drm/i915/hwmon: Get rid of devm
Date: Fri, 12 Apr 2024 17:10:31 -0700 [thread overview]
Message-ID: <20240413001031.481961-1-ashutosh.dixit@intel.com> (raw)
When both hwmon and hwmon drvdata (on which hwmon depends) are device
managed resources, the expectation, on device unbind, is that hwmon will be
released before the drvdata. However, it appears devres does not do this
consistently, so that we occasionally see drvdata being released before
hwmon itself. This results in a uaf if hwmon sysfs is accessed during
device unbind.
The only way out of this seems to be do get rid of devm_ and release/free
everything explicitly during device unbind.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10366
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
---
drivers/gpu/drm/i915/i915_hwmon.c | 46 ++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 8c3f443c8347..5f6022b148d7 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -792,7 +792,7 @@ void i915_hwmon_register(struct drm_i915_private *i915)
if (!IS_DGFX(i915))
return;
- hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
+ hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
if (!hwmon)
return;
@@ -818,10 +818,10 @@ void i915_hwmon_register(struct drm_i915_private *i915)
hwm_get_preregistration_info(i915);
/* hwmon_dev points to device hwmon<i> */
- hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name,
- ddat,
- &hwm_chip_info,
- hwm_groups);
+ hwmon_dev = hwmon_device_register_with_info(dev, ddat->name,
+ ddat,
+ &hwm_chip_info,
+ hwm_groups);
if (IS_ERR(hwmon_dev)) {
i915->hwmon = NULL;
return;
@@ -838,10 +838,10 @@ void i915_hwmon_register(struct drm_i915_private *i915)
if (!hwm_gt_is_visible(ddat_gt, hwmon_energy, hwmon_energy_input, 0))
continue;
- hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat_gt->name,
- ddat_gt,
- &hwm_gt_chip_info,
- NULL);
+ hwmon_dev = hwmon_device_register_with_info(dev, ddat_gt->name,
+ ddat_gt,
+ &hwm_gt_chip_info,
+ NULL);
if (!IS_ERR(hwmon_dev))
ddat_gt->hwmon_dev = hwmon_dev;
}
@@ -849,5 +849,31 @@ void i915_hwmon_register(struct drm_i915_private *i915)
void i915_hwmon_unregister(struct drm_i915_private *i915)
{
- fetch_and_zero(&i915->hwmon);
+ struct i915_hwmon *hwmon;
+ struct hwm_drvdata *ddat;
+ struct intel_gt *gt;
+ int i;
+
+ hwmon = fetch_and_zero(&i915->hwmon);
+ if (!hwmon)
+ return;
+
+ ddat = &hwmon->ddat;
+
+ for_each_gt(gt, i915, i) {
+ struct hwm_drvdata *ddat_gt;
+
+ ddat_gt = hwmon->ddat_gt + i;
+
+ if (ddat_gt->hwmon_dev) {
+ hwmon_device_unregister(ddat_gt->hwmon_dev);
+ ddat_gt->hwmon_dev = NULL;
+ }
+ }
+
+ if (ddat->hwmon_dev)
+ hwmon_device_unregister(ddat->hwmon_dev);
+
+ mutex_destroy(&hwmon->hwmon_lock);
+ kfree(hwmon);
}
--
2.41.0
next reply other threads:[~2024-04-13 0:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-13 0:10 Ashutosh Dixit [this message]
2024-04-13 14:43 ` [PATCH] drm/i915/hwmon: Get rid of devm Armin Wolf
2024-04-15 23:21 ` Dixit, Ashutosh
2024-04-14 23:23 ` Dixit, Ashutosh
-- strict thread matches above, loose matches on Subject: below --
2024-04-16 3:55 Ashutosh Dixit
2024-04-17 14:56 Ashutosh Dixit
2024-04-18 21:56 ` Andi Shyti
2024-04-19 1:05 ` Dixit, Ashutosh
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