Bug 2540445 (CVE-2026-93815)

Summary: CVE-2026-93815 kernel: net: au1000: move free_irq out of the close-time spinlocked section
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: 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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Doc Text:
A flaw was found in the Linux kernel's Au1000 Ethernet driver. This vulnerability allows a privileged local user to cause a Denial of Service (DoS) when disabling or closing the network interface. The issue occurs because the driver executes a sleepable interrupt cleanup routine while holding an atomic lock, which can trigger a kernel crash.
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Description OSIDB Bzimport 2026-09-24 16:51:39 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: au1000: move free_irq out of the close-time spinlocked section

au1000_close() calls free_irq() while aup->lock is still held with
spin_lock_irqsave(). free_irq() can sleep because it takes the IRQ
descriptor request mutex, so it does not belong inside the close-time
spinlocked section.

This was found by our static analysis tool and then confirmed by manual
review of the in-tree au1000_close() .ndo_stop path. The reviewed path
keeps aup->lock held across the MAC reset, queue stop and
free_irq(dev->irq, dev).

A directed runtime validation kept that ndo_stop carrier and the same
free_irq(dev->irq, dev) operation under the driver lock. Lockdep reported
"BUG: sleeping function called from invalid context" and "Invalid wait
context" while free_irq() was taking desc->request_mutex, with
au1000_close() and free_irq() on the stack.

Drop aup->lock before freeing the IRQ. The protected close-time work still
stops the device and queue before IRQ teardown, but the sleepable IRQ core
path now runs outside the spinlocked section.
Comment 1 Mauro Matteo Cascella 2026-09-28 13:54:54 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93815.mbox