[PATCH v2 1/2] dmaengine: idxd: Do not call destroy_workqueue with null idxd->wq

[Steve Wahl]

Error paths within idxd_pci_probe_alloc and related functions end up
calling destroy_workqueue with a null pointer, from
idxd_conf_device_release via put_device, because that allocation has
not yet occurred when the error is hit.

This was encountered running in a kexec'd kdump kernel with reduced
resources, causing the "Device is HALTED!" branch in
idxd_device_init_reset to be taken.

In idxd_conf_device_release, check that the workqueue has been
allocated before trying to destroy it.

Fixes: 3d33de353b1f ("dmaengine: idxd: Fix not releasing workqueue on .release()")

Signed-off-by: Steve Wahl <steve.wahl@xxxxxxx>
---
v2: split into two patches as requested by Vinicius Costa

 drivers/dma/idxd/sysfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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);
-- 
2.51.0