Hi Sasha, Am 13.11.2019 um 14:27 schrieb Sasha Levin:
On Tue, Nov 12, 2019 at 03:52:47PM +1300, Michael Schmitz wrote:Dear stable kernel maintainers, please consider including commit 9393c8de628c ("scsi: core: Handle drivers which set sg_tablesize to zero") for inclusion in stable. The commit fixes a long standing bug that affects all SCSI low-level drivers setting sg_tablesize to zero, introduced in commit d285203c ("scsi: add support for a blk-mq based I/O path.") around kernel version 3.16. Use of the option use_blk_mq=y in kernel versions prior to 5.1, and any use of such drivers in later kernels, will result in a null pointer dereference from the block layer. I hadn't expected Martin Petersen to pick my fix over another one submitted by Finn Thain, so I never added CC: or Fixes: tags.Could you provide a backport for 4.19 and older? We would need to work around not having 3dccdf53c2f3 ("scsi: core: avoid preallocating big SGL for data") in older kernels, and I'm not confident about what I ended up as a backport without ability to test it.
I hadn't spotted that. From what I've seen, that commit renamed scsi_mq_inline_sgl_size() by scsi_mq_sgl_size() (among all the other changes) so modifying my patch with that in mind should suffice.
For safety, I'll test that version though. Cheers, Michael
