CVE-2026-64583: usb: gadget: udc: bdc: free IRQ and drain func_wake_notify before teardown

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

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

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: udc: bdc: free IRQ and drain func_wake_notify before teardown

The Broadcom BDC UDC driver registers its IRQ handler with
devm_request_irq() in bdc_udc_init(), so the IRQ is released by devm
only after bdc_remove() returns.  devm releases resources in reverse
LIFO order, but bdc_remove() runs bdc_udc_exit() and bdc_hw_exit() ->
bdc_mem_free() manually before returning: bdc_udc_exit() tears down
individual endpoint objects via bdc_free_ep(), while bdc_hw_exit() ->
bdc_mem_free() frees and NULLs the DMA-coherent status-report ring
(bdc->srr.sr_bds) and kfree()s bdc->bdc_ep_array.  Both happen while
the IRQ handler (bdc_udc_interrupt, requested with IRQF_SHARED)
remains deliverable in the window up to the post-remove devm
free_irq().

On receipt of a shared interrupt in that window, bdc_udc_interrupt()
dereferences bdc->srr.sr_bds[bdc->srr.dqp_index] (NULL or freed DMA)
and dispatches sr_handler callbacks that index into bdc_ep_array,
causing a NULL-deref or use-after-free.

The same window affects the delayed_work bdc->func_wake_notify, which is
armed from the IRQ handler via bdc_sr_uspc() -> handle_link_state_change()
-> schedule_delayed_work() and may self-rearm from its own callback
bdc_func_wake_timer().  No cancel exists anywhere in the driver, so a
queued work item that fires after bdc_remove() returns and the bdc
structure is devm-freed dereferences freed memory.

Replace devm_request_irq() with request_irq() and add an explicit
free_irq(bdc->irq, bdc) in bdc_remove().  Clear BDC_GIE before
free_irq() to stop the device from asserting interrupts, then
free_irq() drains any in-flight handler, then cancel_delayed_work_sync()
drains the func_wake_notify delayed work.  This ordering ensures the
IRQ handler and delayed work cannot interfere with the subsequent
endpoint and DMA teardown in bdc_udc_exit() and bdc_hw_exit().  Wire the
matching free_irq() into the bdc_udc_init() error path so the IRQ is
released on probe failure, and route the bdc_init_ep() failure through
err0 instead of returning directly.

This issue was found by an in-house static analysis tool.

The Linux kernel CVE team has assigned CVE-2026-64583 to this issue.


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

	Issue introduced in 3.19 with commit efed421a94e62a7ddbc76acba4312b70e4be958f and fixed in 6.6.148 with commit 1a1d7158420df6b8fa1efc0cdd6ab704801a4fc8
	Issue introduced in 3.19 with commit efed421a94e62a7ddbc76acba4312b70e4be958f and fixed in 6.12.101 with commit f6fc21ec7ccd83726ba766d73d0b8cc03e726475
	Issue introduced in 3.19 with commit efed421a94e62a7ddbc76acba4312b70e4be958f and fixed in 6.18.42 with commit dcf3e2f164435b5844706cb8eefef29ebee0eedb
	Issue introduced in 3.19 with commit efed421a94e62a7ddbc76acba4312b70e4be958f and fixed in 7.1.6 with commit d4964a74717107697999f48bcb4e80a9c0679a27
	Issue introduced in 3.19 with commit efed421a94e62a7ddbc76acba4312b70e4be958f and fixed in 7.2-rc5 with commit 0583f2fbf8f86ae3a0ce054f96783dd83e65d9bb

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-2026-64583
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/gadget/udc/bdc/bdc_core.c
	drivers/usb/gadget/udc/bdc/bdc_udc.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/1a1d7158420df6b8fa1efc0cdd6ab704801a4fc8
	https://git.kernel.org/stable/c/f6fc21ec7ccd83726ba766d73d0b8cc03e726475
	https://git.kernel.org/stable/c/dcf3e2f164435b5844706cb8eefef29ebee0eedb
	https://git.kernel.org/stable/c/d4964a74717107697999f48bcb4e80a9c0679a27
	https://git.kernel.org/stable/c/0583f2fbf8f86ae3a0ce054f96783dd83e65d9bb