Bug 2516771 (CVE-2026-74405)

Summary: CVE-2026-74405 kernel: OPP: Fix race between OPP addition and lookup
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. A race condition exists within the Optimized Power Performance (OPP) subsystem, where a newly added OPP object is exposed before its internal reference count is fully initialized. A concurrent operation can then increment this uninitialized reference count, leading to data corruption. This corruption can cause the object to be prematurely released, potentially resulting in system instability or a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-15 06:32:39 UTC
In the Linux kernel, the following vulnerability has been resolved:

OPP: Fix race between OPP addition and lookup

A race exists between dev_pm_opp_add_dynamic() and
dev_pm_opp_find_freq_exact():

  CPU0 (add)                          CPU1 (lookup)
  -------------------------------     ------------------------------
  _opp_add()
    mutex_lock()
    list_add(&new_opp->node, head)
    mutex_unlock()                    _opp_table_find_key()
                                        mutex_lock()
                                        dev_pm_opp_get(opp)
                                          kref_get()
                                        mutex_unlock()
    kref_init(&new_opp->kref)
                                      dev_pm_opp_put()
                                        kref_put_mutex()

The newly added OPP is inserted into the list before its kref is
initialized. A concurrent lookup can find this OPP and increment its
reference count while it is still uninitialized, leading to refcount
corruption and a potential premature free.

Fix this by initializing ->kref and ->opp_table before making the OPP
visible via list_add(). This ensures any concurrent lookup observes a
fully initialized object.

[ Viresh: Updated commit log ]