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

scsi: core: pair EH runtime PM get and put

shost->eh_noresume is currently consulted twice in one error handling
iteration: once before scsi_autopm_get_host() and once again before
scsi_autopm_put_host().

That is racy when a PM-triggered error path flips shost->eh_noresume
while the SCSI EH thread is still running.

The problem flow looks like this:
PM path
  ufshcd_set_dev_pwr_mode()
    shost->eh_noresume = 1
    ufshcd_execute_start_stop  <-- trigger EH
    ...
    shost->eh_noresume = 0

EH path
  scsi_error_handler()
    if (!shost->eh_noresume)
      scsi_autopm_get_host()  <-- skipped
    ...
    if (!shost->eh_noresume)
       scsi_autopm_put_host()  <-- executed later

In that case one EH iteration can skip autoresume on entry and still
drop a runtime PM reference on exit. That leaves an unmatched runtime PM
put and can trigger a runtime PM usage count underflow.

Fix this by making eh_noresume a regular bool so it can be accessed with
READ_ONCE() and WRITE_ONCE(). Snapshot it once per EH iteration and use
that snapshot for both runtime PM get and put decisions.