Bug 2559632 (CVE-2026-98953)

Summary: CVE-2026-98953 kernel: devlink: fix devlink_rel reference leak when notify work is pending
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's devlink subsystem. An improper reference count management issue occurs when scheduling notification work for nested devlink instances that are already pending. A local user could exploit this flaw by repeatedly registering and unregistering nested devlink instances, causing a memory leak that can lead to resource exhaustion and a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-23 12:47:00 UTC 
In the Linux kernel, the following vulnerability has been resolved:

devlink: fix devlink_rel reference leak when notify work is pending

devlink_rel_nested_in_notify_work_schedule() takes a reference on the
devlink_rel for the notify work and then queues the work, ignoring the
return value of schedule_delayed_work(). If the work is already pending,
nothing new is queued, the work runs only once and drops only one
reference, so the extra one is leaked together with the devlink_rel and
its index in devlink_rels.

This is easy to hit. devl_register() of a nested instance queues the
work, and if the instance is unregistered before the work has run,
devlink_rel_put() queues it again while it is still pending. The work
also keeps rescheduling itself for as long as the parent devlink lock
cannot be taken, which widens the window. Registering and unregistering
a nested devlink instance 100 times while holding the parent lock leaks
all 100 devlink_rel objects.

The reschedule path in devlink_rel_nested_in_notify_work() has the same
problem: if the work was queued again while it was running, the
reference it holds is never dropped.

Drop the reference in both places when the work was already pending.
The pending work holds its own reference, so this can not be the last
one.