In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Avoid req_q_map double-read in qla2x00_error_entry() qla2x00_error_entry() reads ha->req_q_map[que] twice: once for the NULL check and again when assign…

Overview

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

scsi: qla2xxx: Avoid req_q_map double-read in qla2x00_error_entry()

qla2x00_error_entry() reads ha->req_q_map[que] twice: once for the NULL check and again when assigning it to req. The map slot is cleared by qla25xx_free_req_que() (ha->req_q_map[que_id] = NULL under mq_lock) during queue teardown, while the response-queue interrupt that drives qla2x00_error_entry() is still registered (the IRQ is released later in qla25xx_free_rsp_que()). If the slot is set to NULL between the two reads, req becomes NULL and is dereferenced.

Read the slot once into req and NULL-check the local before use. mq_lock is a mutex and cannot be taken from interrupt context, so the single read plus local check is the appropriate fix for the reported NULL dereference.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.