From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

[ Upstream commit 3d33de353b1ff9023d5ec73b9becf80ea87af695 ]

The workqueue associated with an DSA/IAA device is not released when
the object is freed.

Fixes: 47c16ac27d4c ("dmaengine: idxd: fix idxd conf_dev 'struct device' lifetime")
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://patch.msgid.link/20260121-idxd-fix-flr-on-kernel-queues-v3-v3-7-7ed70658a9d1@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
[ Remove destroy_workqueue(idxd->wq) from the function idxd_remove() to
avoid the workqueue is released twice. ]
Signed-off-by: Wenshan Lan <jetlan9@163.com>
---
On 5.15.x, destroy_workqueue(idxd->wq) is still called directly in 
idxd_remove(). Applying the upstream patch as-is would cause a double
destroy: 
once in idxd_remove() and again in idxd_conf_device_release() when 
put_device() triggers the release callback.

Resolution: In addition to adding destroy_workqueue(idxd->wq) to 
idxd_conf_device_release(), the call was removed from idxd_remove(). 
This is safe because idxd_remove() ends with
put_device(idxd_confdev(idxd)) which drops the last reference and 
triggers idxd_conf_device_release(), where the workqueue is now destroyed.

---
 drivers/dma/idxd/init.c  | 1 -
 drivers/dma/idxd/sysfs.c | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index f2d27c6ec1ce..698387103da7 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -829,7 +829,6 @@ static void idxd_remove(struct pci_dev *pdev)
 	pci_iounmap(pdev, idxd->reg_base);
 	iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
 	pci_disable_device(pdev);
-	destroy_workqueue(idxd->wq);
 	perfmon_pmu_remove(idxd);
 	put_device(idxd_confdev(idxd));
 }
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 489a9d885076..ee208dfdd0cb 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -1271,6 +1271,7 @@ static void idxd_conf_device_release(struct device *dev)
 {
 	struct idxd_device *idxd = confdev_to_idxd(dev);
 
+	destroy_workqueue(idxd->wq);
 	kfree(idxd->groups);
 	kfree(idxd->wqs);
 	kfree(idxd->engines);
-- 
2.43.0

On Mon, Jun 01, 2026 at 01:24:12PM +0800, Wenshan Lan wrote:
> [PATCH 5.15.y] dmaengine: idxd: Fix not releasing workqueue on .release()

Now applied to 5.15.y as dd377066acf6a4 (backport of upstream
3d33de353b1f).

Thanks,
Sasha