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.
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Thanks,
Sasha
