Bug 2464374 (CVE-2026-31756)

Summary: CVE-2026-31756 kernel: usb: dwc2: gadget: Fix spin_lock/unlock mismatch in dwc2_hsotg_udc_stop()
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
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's dwc2 USB gadget driver. A local user could trigger an incorrect locking sequence within the dwc2_hsotg_udc_stop() function. This issue, a spin_lock/unlock mismatch, can lead to a system deadlock, causing a Denial of Service (DoS) for the affected system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-01 15:03:06 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: dwc2: gadget: Fix spin_lock/unlock mismatch in dwc2_hsotg_udc_stop()

dwc2_gadget_exit_clock_gating() internally calls call_gadget() macro,
which expects hsotg->lock to be held since it does spin_unlock/spin_lock
around the gadget driver callback invocation.

However, dwc2_hsotg_udc_stop() calls dwc2_gadget_exit_clock_gating()
without holding the lock. This leads to:
 - spin_unlock on a lock that is not held (undefined behavior)
 - The lock remaining held after dwc2_gadget_exit_clock_gating() returns,
   causing a deadlock when spin_lock_irqsave() is called later in the
   same function.

Fix this by acquiring hsotg->lock before calling
dwc2_gadget_exit_clock_gating() and releasing it afterwards, which
satisfies the locking requirement of the call_gadget() macro.
Comment 1 Keith Grant 2026-05-01 22:23:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050144-CVE-2026-31756-87ec@gregkh/T