Re: [PATCH] scsi: megaraid: Fix uninitialized mbox in mega_cmd_done

From: Martin K. Petersen
Date: Wed May 31 2023 - 18:38:52 EST

Hi Maximilian!

> This is similar to commit 7a2ae008a53c ("scsi: megaraid: Fix
> mega_cmd_done() CMDID_INT_CMDS").

That's supposed to be commit 75cb113cd43f, right?

> When cmdid == CMDID_INT_CMDS and status != 0 then mbox is still NULL
> but is dereferenced below.

Is this actually a valid scenario, though? The mbox is only dereferenced
if there is status returned from an attached device. And I am guessing
that a controller-internal command does not talk to any attached device.
Thus status should always be 0 for CMDID_INT_CMDS. I don't have the
megaraid firmware manual so this is pure guesswork on my part. But you
would think we would have come across an invalid deref since the
original 2014 commit made the offending change.

Martin K. Petersen Oracle Linux Engineering