[PATCH v2 21/30] cxlflash: Fix to prevent workq from accessing freed memory

[Matthew R. Ochs]

The workq can process work in parallel with a remove event, leading
to a condition where the workq handler can access freed memory.

To remedy, the workq should be terminated prior to freeing memory. Move
the termination call earlier in remove and use cancel_work_sync() instead
of flush_work() as there is not a need to process any scheduled work when
shutting down.

Signed-off-by: Matthew R. Ochs <mrochs at linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj at linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 1856a73..1625aea 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -736,12 +736,12 @@ static void cxlflash_remove(struct pci_dev *pdev)
 		scsi_remove_host(cfg->host);
 		/* Fall through */
 	case INIT_STATE_AFU:
+		cancel_work_sync(&cfg->work_q);
 		term_afu(cfg);
 	case INIT_STATE_PCI:
 		pci_release_regions(cfg->dev);
 		pci_disable_device(pdev);
 	case INIT_STATE_NONE:
-		flush_work(&cfg->work_q);
 		free_mem(cfg);
 		scsi_host_put(cfg->host);
 		break;
-- 
2.1.0