enclosure: Fix stale device oops with hot replug

Commit Message

James Bottomley Jan. 9, 2020, 1:21 a.m. UTC

Doing an add/remove/add on a SCSI device in an enclosure leads to an
oops caused by poisoned values in the enclosure device list pointers.
The reason is because we are keeping the enclosure device across the
enclosed device add/remove/add but the current code is doing a
device_add/device_del/device_add on it.  This is the wrong thing to do
in sysfs, so fix it by not doing a device_del on the enclosure device
simply because of a hot remove of the drive in the slot.

Fixes: 43d8eb9cfd0a ("[SCSI] ses: add support for enclosure component hot removal")
Reported-by: Luo Jiaxing 
Tested-by: John Garry 
Signed-off-by: James Bottomley 
---
 drivers/misc/enclosure.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Martin K. Petersen Jan. 10, 2020, 6:39 a.m. UTC | #1

James,

> Doing an add/remove/add on a SCSI device in an enclosure leads to an
> oops caused by poisoned values in the enclosure device list pointers.
> The reason is because we are keeping the enclosure device across the
> enclosed device add/remove/add but the current code is doing a
> device_add/device_del/device_add on it.  This is the wrong thing to do
> in sysfs, so fix it by not doing a device_del on the enclosure device
> simply because of a hot remove of the drive in the slot.

Applied to 5.5/scsi-fixes...

> Fixes: 43d8eb9cfd0a ("[SCSI] ses: add support for enclosure component hot removal")
> Reported-by: Luo Jiaxing 
> Tested-by: John Garry 
> Signed-off-by: James Bottomley 

...and filled out the blanks.

Patch

diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
index 6d27ccfe0680..3c2d405bc79b 100644
--- a/drivers/misc/enclosure.c
+++ b/drivers/misc/enclosure.c
@@ -406,10 +406,9 @@  int enclosure_remove_device(struct enclosure_device *edev, struct device *dev)
 		cdev = &edev->component[i];
 		if (cdev->dev == dev) {
 			enclosure_remove_links(cdev);
-			device_del(&cdev->cdev);
 			put_device(dev);
 			cdev->dev = NULL;
-			return device_add(&cdev->cdev);
+			return 0;
 		}
 	}
 	return -ENODEV;