Bug 2493699 (CVE-2026-53323)

Summary: CVE-2026-53323 kernel: net: dsa: remove redundant netdev_lock_ops() from conduit ethtool ops
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
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 Distributed Switch Architecture (DSA) subsystem. Redundant locking operations within the DSA conduit ethtool wrappers can lead to a deadlock. A local attacker can exploit this by using the `ethtool -i` command, causing the system to become unresponsive and resulting in a denial of service.
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Description OSIDB Bzimport 2026-06-26 21:01:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: dsa: remove redundant netdev_lock_ops() from conduit ethtool ops

DSA replaces the conduit (master) device's ethtool_ops with its own
wrappers that aggregate stats from both the conduit and DSA switch
ports. Taking the lock again inside the DSA wrappers causes a deadlock.

Stumbled upon this when booting qemu with fbnic and CONFIG_NET_DSA_LOOP=y
(which looks like some kind of testing device that auto-populates the ports
of eth0). `ethtool -i` is enough to deadlock. This means we have basically zero
coverage for DSA stuff with real ops locked devs.

Remove the redundant netdev_lock_ops()/netdev_unlock_ops() calls from
the DSA conduit ethtool wrappers.
Comment 1 Mauro Matteo Cascella 2026-06-29 11:10:16 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062623-CVE-2026-53323-7827@gregkh/T