[PATCH] dmaengine: idxd: Avoid destroying the device workqueue twice

[Yao Kai <yaokai34@huawei.com>]

If idxd_probe() fails after idxd_setup_internals() succeeds,
idxd_cleanup_internals() destroys idxd->wq. The PCI probe error path
then calls idxd_free(), whose put_device() invokes
idxd_conf_device_release() and destroys the same workqueue again.
The err_evl path in idxd_setup_internals() has the same problem.
This can corrupt the workqueue list or access freed memory.

Clear idxd->wq after both error-path destroy_workqueue() calls and
only destroy a non-NULL workqueue in the release callback. The NULL
check also handles failures before the workqueue is created, while
preserving its destruction on normal device removal.

Fixes: 3d33de353b1f ("dmaengine: idxd: Fix not releasing workqueue on .release()")
Cc: stable@vger.kernel.org
Signed-off-by: Yao Kai <yaokai34@huawei.com>
---
 drivers/dma/idxd/init.c  | 2 ++
 drivers/dma/idxd/sysfs.c | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 4b827a329756..ffbc5a74be6e 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -389,6 +389,7 @@ static void idxd_cleanup_internals(struct idxd_device *idxd)
 	idxd_clean_engines(idxd);
 	idxd_clean_wqs(idxd);
 	destroy_workqueue(idxd->wq);
+	idxd->wq = NULL;
 }
 
 static int idxd_init_evl(struct idxd_device *idxd)
@@ -460,6 +461,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
 
  err_evl:
 	destroy_workqueue(idxd->wq);
+	idxd->wq = NULL;
  err_wkq_create:
 	idxd_clean_groups(idxd);
  err_group:
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 6d251095c350..d5ffc641c856 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -1836,7 +1836,8 @@ static void idxd_conf_device_release(struct device *dev)
 {
 	struct idxd_device *idxd = confdev_to_idxd(dev);
 
-	destroy_workqueue(idxd->wq);
+	if (idxd->wq)
+		destroy_workqueue(idxd->wq);
 	kfree(idxd->groups);
 	bitmap_free(idxd->wq_enable_map);
 	kfree(idxd->wqs);
-- 
2.43.0