Description
In the Linux kernel, the following vulnerability has been resolved:
dm: limit target bio polling to one shot
dm_poll_bio() is the ->poll_bio() callback for a stacked dm device. The caller only knows about the dm queue, so it may decide to do a spinning poll if it thinks a single queue is being polled. Passing those flags unchanged to the mapped clone lets blk_mq_poll() spin on a target queue from inside dm_poll_bio().
With io_uring IOPOLL on a dm-stripe target this can keep a task in
dm_poll_bio() -> bio_poll() -> blk_mq_poll()
long enough to trigger an RCU CPU stall, before io_uring gets back to io_iopoll_check() and its need_resched() check.
Keep dm's ->poll_bio() bounded by forcing one-shot polling for target bios. The caller can invoke dm_poll_bio() again if it wants to keep polling, and it also gets a chance to reap completions or reschedule between passes.
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
No affected versions have been published.
Timeline
- Published
- Aug 15, 2026
- Last modified
- Aug 17, 2026
- NVD status
- Received