[LU-6656] Non atomic allocation under spin lock in qmt_glimpse_lock

• Type: Bug
• Resolution: Not a Bug
• Priority: Minor
• Affects Version/s: Lustre 2.8.0
• Severity: 3
• Assignee: WC Triage
• Reporter: Patrick Farrell

Description

In qmt_glimpse_lock:

While the resource lock (a spin lock) is held, it does

OBD_ALLOC_PTR(work);

This allocation is not atomic, so it can potentially sleep.

Sleeping with a spinlock held is not a good idea in general, and (per Andreas) it is specifically not allowed for GFP_NOFS allocations.