CVE-2026-74725: enic: fix tx_hang_reset use-after-free on device removal

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

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

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

enic: fix tx_hang_reset use-after-free on device removal

enic_remove() cancels the reset and change_mtu_work items but does not
cancel tx_hang_reset. A TX timeout that fires while the device is being
removed can schedule enic_tx_hang_reset() so that it runs after
free_netdev(), resulting in a use-after-free.

cancel_work_sync() alone is not sufficient here: the still-live watchdog
and notify paths can re-schedule these work items in the window between
the cancel and unregister_netdev(). Use disable_work_sync(), which
cancels the work and blocks any subsequent schedule_work() from
requeuing it, and apply it to the reset and change_mtu_work items as
well so the same requeue race is closed for all teardown work.

The Linux kernel CVE team has assigned CVE-2026-74725 to this issue.


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

	Issue introduced in 4.4 with commit 937317c7c1097aa878a5000e3aab616eb5c590c0 and fixed in 6.12.104 with commit 8619865f34fb3b130b567855382a5c4aadd522b9
	Issue introduced in 4.4 with commit 937317c7c1097aa878a5000e3aab616eb5c590c0 and fixed in 6.18.45 with commit e506e704b74748ffd0e1c92a7453ca2a959f832b
	Issue introduced in 4.4 with commit 937317c7c1097aa878a5000e3aab616eb5c590c0 and fixed in 7.1.9 with commit 4f3464fc6c1f26afc504fd525c574f2bc14c9d42
	Issue introduced in 4.4 with commit 937317c7c1097aa878a5000e3aab616eb5c590c0 and fixed in 7.2 with commit ec680ea4ba1bca92a767fb7e7869758bfdd886e3

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-2026-74725
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/net/ethernet/cisco/enic/enic_main.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/8619865f34fb3b130b567855382a5c4aadd522b9
	https://git.kernel.org/stable/c/e506e704b74748ffd0e1c92a7453ca2a959f832b
	https://git.kernel.org/stable/c/4f3464fc6c1f26afc504fd525c574f2bc14c9d42
	https://git.kernel.org/stable/c/ec680ea4ba1bca92a767fb7e7869758bfdd886e3