The SCSI generic driver is currently broken in the 3.18, 4.1, 4.4, and 4.9 stable kernels. This is the problematic commit:
109bade9c625 ("scsi: sg: use standard lists for sg_requests")
(all commit ids are from upstream git, not stable.git)
There have already been a number of fixes backported to -stable to fix problems introduced by that commit:
bd46fc406b30 ("scsi: sg: off by one in sg_ioctl()") 4759df905a47 ("scsi: sg: factor out sg_fill_request_table()") 3e0097499839 ("scsi: sg: fixup infoleak when using SG_GET_REQUEST_TABLE") 587c3c9f286c ("scsi: sg: Re-fix off by one in sg_fill_request_table()")
I am not sure why 109bade9c625 was added to -stable to begin with. My guess is that the "infoleak" fix was flagged as being appropriate for -stable, and it depended on the original commit 109bade9c625. But if you take a close look, the original commit 109bade9c625 is what introduced the infoleak in the first place. Or maybe there was some other reason. But I digress.
There is one more fix for 109bade9c625 that has not yet been backported:
48ae8484e9fc ("scsi: sg: don't return bogus Sg_requests")
Without the fix above, sg oopses as soon as I try to use it. So please add 48ae8484e9fc to -stable.
The following -stable kernels already have 48ae8484e9fc: 4.14.31 4.15.14
The following -stable kernels need 48ae8484e9fc: 3.18.102 4.1.51 4.4.125 4.9.91
The following -stable kernels are not affected because they have not had the problematic commit backported: 3.2.101 3.16.56
Related bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198081
Thanks! Tony Battersby Cybernetics