CVE-2026-64465: usb: xhci: Fix sleep in atomic context in xhci_free_streams()

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2026-64465 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 5.10.261 with commit e623e4a203f56d5c57519a9a3cb29600551534ad
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 5.15.212 with commit d107eb316144c5fb958486e7fe604cd7f1b35cda
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 6.1.178 with commit 1e45aa722c4ce5663e987102aac18c8ad6a83fdd
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 6.6.145 with commit 10666ac9c552990204e791af653abf8e9d9ff619
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 6.12.96 with commit f7b022ae07685e7526fc39f387ce65b5d309dd3b
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 6.18.39 with commit f90586129cf9e1fbdb718ef602eea3f15dc1c31c
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 7.1.4 with commit 93cd037da94fcb93183bfb2457e3a56d3eb4c8f4
	Issue introduced in 2.6.35 with commit 8df75f42f8e67e2851cdcf6da91640fb881defd1 and fixed in 7.2-rc3 with commit 42c37c4b75d38b51d84f31a8e29427f5e06a7c2a

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64465
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/usb/host/xhci.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/e623e4a203f56d5c57519a9a3cb29600551534ad
	https://git.kernel.org/stable/c/d107eb316144c5fb958486e7fe604cd7f1b35cda
	https://git.kernel.org/stable/c/1e45aa722c4ce5663e987102aac18c8ad6a83fdd
	https://git.kernel.org/stable/c/10666ac9c552990204e791af653abf8e9d9ff619
	https://git.kernel.org/stable/c/f7b022ae07685e7526fc39f387ce65b5d309dd3b
	https://git.kernel.org/stable/c/f90586129cf9e1fbdb718ef602eea3f15dc1c31c
	https://git.kernel.org/stable/c/93cd037da94fcb93183bfb2457e3a56d3eb4c8f4
	https://git.kernel.org/stable/c/42c37c4b75d38b51d84f31a8e29427f5e06a7c2a