Bug 2540531 (CVE-2026-97477)

Summary: CVE-2026-97477 kernel: RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind()
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: 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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A flaw was found in the Linux kernel's Remote Direct Memory Access (RDMA) subsystem. An error-handling issue during counter allocation and queue pair binding neglects to decrement the active counter tally when a bind attempt fails. A local user can exploit this flaw by triggering repeated binding failures, which leaks counter references and permanently prevents the port from switching operational modes, resulting in a denial of service.
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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 2026-09-24 17:08:18 UTC 
In the Linux kernel, the following vulnerability has been resolved:

RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind()

When __rdma_counter_bind_qp() fails in alloc_and_bind(), the error path
jumps to err_mode which frees the counter without decrementing
port_counter->num_counters. The only place that decrements is
rdma_counter_free(), which is unreachable since the counter was never
successfully bound.

This leak accumulates across repeated failures, permanently preventing
the port from switching to AUTO mode (-EBUSY in __counter_set_mode())
and blocking the MANUAL→NONE auto-revert in rdma_counter_free(). When
the mode was NONE before the call, the MANUAL mode set by
__counter_set_mode() also leaks since the revert logic is never
reached.

Add an err_bind label between the num_counters increment and the
existing err_mode label. It decrements num_counters and mirrors the
MANUAL→NONE revert from rdma_counter_free(), ensuring the port state
is fully restored on bind failure.
Comment 1 Mauro Matteo Cascella 2026-09-29 18:51:50 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97477.mbox