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

IB/IPoIB: Avoid restoring OPER_UP after multicast flush

ipoib_ib_dev_flush_light() temporarily clears IPOIB_FLAG_OPER_UP to
prevent multicast joins while ipoib_mcast_dev_flush() is running, and
restores the flag afterwards if it was previously set.

This restore races with ipoib_ib_dev_down(). If the interface is brought
down while the flush is in progress, ipoib_ib_dev_down() clears
IPOIB_FLAG_OPER_UP, but the flush path may set it again after the device
has already gone down.

Since commit 894021a75291 ("IB/ipoib: Make the carrier_on_task race
aware"), ipoib_mcast_carrier_on_task() relies on IPOIB_FLAG_OPER_UP
being cleared to terminate its rtnl_trylock() retry loop. If the flag is
left set after shutdown, the workqueue retries forever, causing teardown
to deadlock when ipoib_ndo_uninit() waits in destroy_workqueue() while
holding RTNL.

Instead of overloading IPOIB_FLAG_OPER_UP to block multicast joins
during a light flush, introduce a dedicated IPOIB_FLAG_MCAST_FLUSH flag.
Use it together with IPOIB_FLAG_OPER_UP to determine whether multicast
joins are allowed, avoiding the race with device shutdown.
Published: 2026-10-06
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Tue, 06 Oct 2026 09:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: IB/IPoIB: Avoid restoring OPER_UP after multicast flush ipoib_ib_dev_flush_light() temporarily clears IPOIB_FLAG_OPER_UP to prevent multicast joins while ipoib_mcast_dev_flush() is running, and restores the flag afterwards if it was previously set. This restore races with ipoib_ib_dev_down(). If the interface is brought down while the flush is in progress, ipoib_ib_dev_down() clears IPOIB_FLAG_OPER_UP, but the flush path may set it again after the device has already gone down. Since commit 894021a75291 ("IB/ipoib: Make the carrier_on_task race aware"), ipoib_mcast_carrier_on_task() relies on IPOIB_FLAG_OPER_UP being cleared to terminate its rtnl_trylock() retry loop. If the flag is left set after shutdown, the workqueue retries forever, causing teardown to deadlock when ipoib_ndo_uninit() waits in destroy_workqueue() while holding RTNL. Instead of overloading IPOIB_FLAG_OPER_UP to block multicast joins during a light flush, introduce a dedicated IPOIB_FLAG_MCAST_FLUSH flag. Use it together with IPOIB_FLAG_OPER_UP to determine whether multicast joins are allowed, avoiding the race with device shutdown.
Title IB/IPoIB: Avoid restoring OPER_UP after multicast flush
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-06T08:46:36.136Z

Reserved: 2026-09-25T10:25:14.343Z

Link: CVE-2026-98347

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-06T09:18:27.773

Modified: 2026-10-06T09:18:27.773

Link: CVE-2026-98347

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses

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