[PATCH v2] scsi: sg: Avoid sg device teardown race

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sg_remove_sfp_usercontext() must not use sg_device_destroy() after
calling scsi_device_put().

sg_device_destroy() is accessing the parent scsi device request_queue.
Which will already be set to NULL when the preceding call to
scsi_device_put() removed the last reference to the parent scsi device.

The resulting NULL pointer exception will then crash the kernel.

Link: https://lore.kernel.org/r/20240305150509.23896-1-Alexander@xxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Wetzel <Alexander@xxxxxxxxxxxxxx>
---
Changes compared to V1:
Reworked the commit message

Alexander
---
 drivers/scsi/sg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 86210e4dd0d3..80e0d1981191 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2232,8 +2232,8 @@ sg_remove_sfp_usercontext(struct work_struct *work)
 			"sg_remove_sfp: sfp=0x%p\n", sfp));
 	kfree(sfp);
 
-	scsi_device_put(sdp->device);
 	kref_put(&sdp->d_ref, sg_device_destroy);
+	scsi_device_put(sdp->device);
 	module_put(THIS_MODULE);
 }
 
-- 
2.44.0





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