From c4a11827b760ef8dcda26b5731d072b1d8fb7c81 Mon Sep 17 00:00:00 2001 From: "Matthew R. Ochs" Date: Fri, 2 Sep 2016 15:40:41 -0500 Subject: [PATCH] scsi: cxlflash: Fix context reference tracking on detach Commit 888baf069f49 ("scsi: cxlflash: Add kref to context") introduced a kref to the context. In particular, the detach routine was updated to use the kref services for managing the removal and destruction of a context. As part of this change, the tracking mechanism internal to the detach handler was refactored. This introduced a bug that can cause the tracking state to be lost. This can lead to a situation where exclusive access to a context is prematurely [and unknowingly] relinquished for the executing thread. To remedy, only update the tracking state when the kref operation indicates the context was removed. Fixes: 888baf069f49 ("scsi: cxlflash: Add kref to context") Signed-off-by: Matthew R. Ochs Acked-by: Uma Krishnan Signed-off-by: Martin K. Petersen --- drivers/scsi/cxlflash/superpipe.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c index c91fe6f..9636970 100644 --- a/drivers/scsi/cxlflash/superpipe.c +++ b/drivers/scsi/cxlflash/superpipe.c @@ -912,7 +912,8 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev, * Release the context reference and the sdev reference that * bound this LUN to the context. */ - put_ctx = !kref_put(&ctxi->kref, remove_context); + if (kref_put(&ctxi->kref, remove_context)) + put_ctx = false; scsi_device_put(sdev); out: if (put_ctx) -- 2.7.4