Description

In the Linux kernel, the following vulnerability has been resolved: blk-mq: avoid double ->queue_rq() because of early timeout David Jeffery found one double ->queue_rq() issue, so far it can be triggered in VM use case because of long vmexit latency or preempt latency of vCPU pthread or long page fault in vCPU pthread, then block IO req could be timed out before queuing the request to hardware but after calling blk_mq_start_request() during ->queue_rq(), then timeout handler may handle it by requeue, then double ->queue_rq() is caused, and kernel panic. So far, it is driver's responsibility to cover the race between timeout and completion, so it seems supposed to be solved in driver in theory, given driver has enough knowledge. But it is really one common problem, lots of driver could have similar issue, and could be hard to fix all affected drivers, even it isn't easy for driver to handle the race. So David suggests this patch by draining in-progress ->queue_rq() for solving this issue.

Affected Products 2

References 3

• git.kernel.org https://git.kernel.org/stable/c/7a73c54a3750895888ab586896736c9434e062a1
  Patch
• git.kernel.org https://git.kernel.org/stable/c/82c229476b8f6afd7e09bc4dc77d89dc19ff7688
  Patch
• git.kernel.org https://git.kernel.org/stable/c/8b3d6b029a552d2978bbac275303d11419826a69
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/7a73c54a3750895888ab586896736c9434e062a1
  Patch
• git.kernel.org https://git.kernel.org/stable/c/82c229476b8f6afd7e09bc4dc77d89dc19ff7688
  Patch
• git.kernel.org https://git.kernel.org/stable/c/8b3d6b029a552d2978bbac275303d11419826a69
  Patch