In the Linux kernel, the following vulnerability has been resolved:

nvme: remove stale namespaces by NSID range during scan

nvme_scan_ns_list() drops the stale namespaces in each gap in the
reported NSID list one NSID at a time. Every iteration calls
nvme_find_get_ns() to look the namespace up and removes it if it is
present. The loop runs once per NSID in the gap rather than once per
namespace actually present.

NSIDs are 32-bit, so a target with a sparse NSID space can make a
single gap spin the loop billions of times with nothing to remove.

  watchdog: BUG: soft lockup - CPU#4 stuck for 26s!
  Workqueue: nvme-wq nvme_scan_work [nvme_core]
  RIP: 0010:__srcu_read_unlock+0xb/0x20
  Call Trace:
   nvme_find_get_ns+0x7d/0xb0 [nvme_core]
   nvme_scan_ns_list+0xe8/0x280 [nvme_core]
   nvme_scan_work+0x18a/0x280 [nvme_core]
   process_one_work+0x197/0x380
   worker_thread+0x2fe/0x410
   kthread+0xe0/0x100

Rename nvme_remove_invalid_namespaces() to nvme_remove_nsid_range()
and give it an open (start, end) NSID range. ctrl->namespaces is
sorted by NSID, so the whole gap is dropped in a single walk that
stops once end is reached. This bounds the work by the namespaces
that are present instead of by the size of the gap.