Bug 2507103 (CVE-2026-64465)

Summary: CVE-2026-64465 kernel: usb: xhci: Fix sleep in atomic context in xhci_free_streams()
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 USB xHCI (eXtensible Host Controller Interface) driver. When a USB device with active stream endpoints is disconnected, the system attempts to free stream resources while holding a lock with interrupts disabled. This can lead to a situation where a function that is designed to sleep is called in an atomic context, triggering a kernel bug and causing a system crash. This vulnerability could allow a local attacker to cause a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-07-25 10:05:10 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: xhci: Fix sleep in atomic context in xhci_free_streams()

When a USB device with active stream endpoints is disconnected,
xhci_free_streams() is called from the hub_event workqueue to
free the stream resources.  It calls xhci_free_stream_info()
while holding xhci->lock with irqs disabled.

xhci_free_stream_info() invokes xhci_free_stream_ctx(), which
calls dma_free_coherent() for large stream context arrays.

dma_free_coherent() can sleep (e.g. via vunmap), triggering
a BUG when called from atomic context.

Call trace:
 dma_free_attrs+0x174/0x220
 xhci_free_stream_info+0xd0/0x11c
 xhci_free_streams+0x278/0x37c
 usb_free_streams+0x98/0xc0
 usb_unbind_interface+0x1b8/0x2f8
 device_release_driver_internal+0x1d4/0x2cc
 device_release_driver+0x18/0x28
 bus_remove_device+0x160/0x1a4
 device_del+0x1ec/0x350
 usb_disable_device+0x98/0x214
 usb_disconnect+0xf0/0x35c
 hub_event+0xab4/0x19ec
 process_one_work+0x278/0x63c

Fix this by saving the stream_info pointers and clearing the
ep references under the lock, then calling xhci_free_stream_info()
outside the lock where sleeping is allowed.
Comment 1 TEJ RATHI 2026-07-30 06:03:39 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072544-CVE-2026-64465-2baa@gregkh/T