Bug 2482551 (CVE-2026-46165)

Summary: CVE-2026-46165 kernel: openvswitch: vport: fix self-deadlock on release of tunnel ports
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
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's openvswitch vport component. This vulnerability arises during the release of tunnel ports, where a self-deadlock can occur. This prevents the vport from being properly freed and its references released, leading to a system deadlock during device removal. Such a deadlock can negatively impact system stability and performance, potentially resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-05-28 11:02:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

openvswitch: vport: fix self-deadlock on release of tunnel ports

vports are used concurrently and protected by RCU, so netdev_put()
must happen after the RCU grace period.  So, either in an RCU call or
after the synchronize_net().  The rtnl_delete_link() must happen under
RTNL and so can't be executed in RCU context.  Calling synchronize_net()
while holding RTNL is not a good idea for performance and system
stability under load in general, so calling netdev_put() in RCU call
is the right solution here.

However,
when the device is deleted, rtnl_unlock() will call netdev_run_todo()
and block until all the references are gone.  In the current code this
means that we never reach the call_rcu() and the vport is never freed
and the reference is never released, causing a self-deadlock on device
removal.

Fix that by moving the rcu_call() before the rtnl_unlock(), so the
scheduled RCU callback will be executed when synchronize_net() is
called from the rtnl_unlock()->netdev_run_todo() while the RTNL itself
is already released.
Comment 1 Keith Grant 2026-05-28 15:25:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052825-CVE-2026-46165-08d2@gregkh/T