Bug 2536323 (CVE-2026-92514)

Summary:	CVE-2026-92514 kernel: RDMA/erdma: Fix CEQ tasklet use-after-free on removal
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	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
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel. When the RDMA/erdma component's Completion Event Queue (CEQ) tasklet is being removed, it can attempt to access memory that has already been released. This 'use-after-free' vulnerability can lead to memory corruption, which might allow an attacker to cause the system to crash (denial of service) or potentially gain elevated privileges.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 17:21:48 UTC

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

RDMA/erdma: Fix CEQ tasklet use-after-free on removal

Each CEQ interrupt handler only schedules eqc->tasklet. The tasklet calls
erdma_ceq_completion_handler(), which reads the DMA-coherent EQ ring
through get_next_valid_eqe() and updates eq->dbrec through notify_eq().

erdma_ceqs_uninit() frees each CEQ IRQ and then destroys its EQ.
free_irq() prevents another hard IRQ and waits for an in-flight handler,
but it does not drain a tasklet that the handler already scheduled. The
tasklet can therefore access eq->qbuf or eq->dbrec after
erdma_eq_destroy() frees them.

Clearing ceq_cb->ready does not synchronize with a tasklet that already
passed the check at the start of erdma_ceq_completion_handler().

Kill the tasklet after free_irq(), when no handler can schedule it again,
and before erdma_ceq_uninit_one() releases the EQ buffers.

Comment 1 gkamathe 2026-09-21 02:21:53 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-92514.mbox