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thermal/debugfs: Prevent use-after-free from occurring after cdev removal
Since thermal_debug_cdev_remove() does not run under cdev->lock, it can
run in parallel with thermal_debug_cdev_state_update() and it may free
the struct thermal_debugfs object used by the latter after it has been
checked against NULL.
If that happens, thermal_debug_cdev_state_update() will access memory
that has been freed already causing the kernel to crash.
Address this by using cdev->lock in thermal_debug_cdev_remove() around
the cdev->debugfs value check (in case the same cdev is removed at the
same time in two different threads) and its reset to NULL.
Fixes: 755113d767
("thermal/debugfs: Add thermal cooling device debugfs information")
Cc :6.8+ <stable@vger.kernel.org> # 6.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
This commit is contained in:
parent
c7f7c37271
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@ -505,15 +505,23 @@ void thermal_debug_cdev_add(struct thermal_cooling_device *cdev)
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*/
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void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
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{
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struct thermal_debugfs *thermal_dbg = cdev->debugfs;
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struct thermal_debugfs *thermal_dbg;
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if (!thermal_dbg)
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mutex_lock(&cdev->lock);
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thermal_dbg = cdev->debugfs;
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if (!thermal_dbg) {
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mutex_unlock(&cdev->lock);
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return;
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}
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cdev->debugfs = NULL;
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mutex_unlock(&cdev->lock);
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mutex_lock(&thermal_dbg->lock);
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thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
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cdev->debugfs = NULL;
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mutex_unlock(&thermal_dbg->lock);
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