CVE-2026-98820blk-mq: set RQF_USE_SCHED when the operation is known

Official description

In the Linux kernel, the following vulnerability has been resolved: blk-mq: set RQF_USE_SCHED when the operation is known The cached requests are allocated for one operation but can be handed out for another. A passthrough command has RQF_USE_SCHED cleared, so using those flags for a subsequent read/write bio will insert it into the scheduler without ->prepare_request() and frees it without ->finish_request(). For kyber, this leaks the domain token acquired at dispatch and stalls the queue. Don't set RQF_USE_SCHED based on the first operation the batch happened to be allocated for. Instead, set it after the request is claimed by an operation. Introduce a helper function, blk_mq_rq_late_init() for this, and absorb blk_mq_rq_time_init() since the two run together.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/790730e4d95de8356a573d4b4864486bba731863
• https://git.kernel.org/stable/c/2c47ebc27fa72078e26177cd458cdaf3006a9685
• https://git.kernel.org/stable/c/ab6c756f28c741d704a7c3e04814bfc3adf6f818