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enclosure: Fix stale device oops with hot replug

PATCH Applied James Bottomley 2 participants 2 messages Jan 9, 2020 – Jan 10, 2020

Subsystems (2)
SCSI Char and misc drivers
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Share & tools
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James Bottomley

author maintainer
#0 lore raw

PATCH 1/1 enclosure: Fix stale device oops with hot replug

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(-)
drivers/misc/enclosure.c +1 -2
index 6d27ccfe0680..3c2d405bc79b 100644
@@ -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;
Signature · 1 line
2.16.4
Applied
#1 lore raw

James,

Quoted 7 lines

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...

Quoted 4 lines
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.

Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering