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

scsi: qla2xxx: Hold qpair lock when sending NVMe LS reject

qla_nvme_ls_reject_iocb() allocates from and advances the request ring
through __qla2x00_alloc_iocbs() (which assumes the hardware_lock is
held) and qla2x00_start_iocbs() (which advances the ring and rings the
request-in doorbell), but takes no lock itself. Two of its callers
invoke it without the producer lock held:

 - qla_nvme_xmt_ls_rsp(), the NVMe-FC .xmt_ls_rsp transport callback, on
   its error path, and

 - qla2xxx_process_purls_pkt(), run from the purex work/DPC context.

Both use ha->base_qpair, whose qp_lock_ptr is hardware_lock, so they can
run concurrently with normal I/O submission on the base ring and corrupt
the ring producer state, leading to duplicated or dropped commands. The
third caller, qla2xxx_process_purls_iocb(), runs inside
qla24xx_process_response_queue() with the qpair lock already held and is
safe; that is also why the lock cannot be taken inside the helper itself
(it would recursively re-acquire hardware_lock on the response path).

Take qp_lock_ptr around the two unlocked callers and document the helper
as caller-locked. Both run in process context, so spin_lock_irqsave() is
used and nothing in the locked region sleeps.