CVE-2026-72495: RDMA/bnxt_re: Avoid repeated requests to allocate WC pages

CVE-2026-72495: RDMA/bnxt_re: Avoid repeated requests to allocate WC pages

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

RDMA/bnxt_re: Avoid repeated requests to allocate WC pages

Applications can request multiple WC pages for the same ucontext.
As of now, only 1 WC page per ucontext is supported. Add a lock to
avoid concurrent access and a check to fail repeated requests.
Also, if the mmap entry insert fails for the WC, free the Doorbell
page index mapped for the WC page.

The Linux kernel CVE team has assigned CVE-2026-72495 to this issue.


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

	Issue introduced in 6.5 with commit 360da60d6c6edb9740de7a8e6d8969d62ceff956 and fixed in 6.18.40 with commit 478c4d24193fe3e6aa2accd4874ae43000e4a217
	Issue introduced in 6.5 with commit 360da60d6c6edb9740de7a8e6d8969d62ceff956 and fixed in 7.1.5 with commit da406b8b49c1dfe661a497483940d7ee781430db
	Issue introduced in 6.5 with commit 360da60d6c6edb9740de7a8e6d8969d62ceff956 and fixed in 7.2-rc1 with commit 441baa79043431807115fd030d7d0bb14ed441a0

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-2026-72495
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/infiniband/hw/bnxt_re/ib_verbs.c
	drivers/infiniband/hw/bnxt_re/ib_verbs.h
	drivers/infiniband/hw/bnxt_re/uapi.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/478c4d24193fe3e6aa2accd4874ae43000e4a217
	https://git.kernel.org/stable/c/da406b8b49c1dfe661a497483940d7ee781430db
	https://git.kernel.org/stable/c/441baa79043431807115fd030d7d0bb14ed441a0