[CVE-2026-72245][LOW] gpu: host1x: Fix device reference leak in host1x_device_parse_dt() error path

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-72245
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: gpu: host1x: Fix device reference leak in host1x_device_parse_dt() error path
Commit: a408d89e20d38d78f540e1951dc4c6056ad662e1
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a408d89e20d38d78f540e1951dc4c6056ad662e1
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72245
Analysis date: Sat, 15 Aug 2026 05:16:42 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A host1x initialization error path used `kfree()` instead of `put_device()` after `device_initialize()`, causing a privileged local device-core reference leak with only theoretical DoS impact from repeated failures.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-72245 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72245

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-72245	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';*CWE-772;*CWE-401;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'host1x_device_add used kfree directly after device_initialize when host1x_device_parse_dt() failed, bypassing normal struct device lifetime handling and leaking the reference held by the embedded device object. The realistic impact is a local resource leak on an initialization error path rather than memory corruption. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over driver initialization, platform device configuration, or device tree related setup. The issue is not network reachable and does not provide a clear confidentiality or integrity primitive. Impact is denial of service only if repeated failures can accumulate leaked resources enough to affect availability.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)	YES	SIMPLEFIX LEAK ERRORPATH HARDWARE LINUS 	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Positive signals:
* Real lifetime / reference-management issue: +1 in paranoid scoring only. The bug is a device-core lifetime mismatch after `device_initialize()`, where `kfree(device)` bypasses `put_device()`.
* Availability impact: +0 conservative, at most +1 paranoid. Repeated failed initialization could theoretically accumulate leaked device-core resources, but no immediate crash, UAF, OOB, write primitive, or strong DoS is shown.

Negative signals:
* Requires admin/root/device-management control in typical deployments: -2. Reliable triggering normally requires control over host1x device initialization, platform device setup, driver probing, or device-tree related configuration.
* Rare / hardware-specific path: -1. The affected path is specific to the Tegra host1x GPU subsystem and an initialization error path.

Not awarded:
* No remote reachability.
* No local unprivileged trigger.
* No generic memory corruption primitive.
* No privilege escalation plausibility.
* No confidentiality or integrity impact.
* No strong kernel crash signal.

## 3. Reachability analysis

The bug is reachable only when `host1x_device_parse_dt()` fails during `host1x_device_add()` after `device_initialize()` has already initialized the embedded `struct device`. In normal deployments, this is a driver initialization / platform-device configuration path, not an ordinary user API.

Namespaces and containers do not meaningfully lower the trigger requirements unless a container or service is delegated host-level device management, which is not typical. The path is not network reachable and is not exposed through a common unprivileged kernel interface.

Call-site confidence: high, because the relevant error path and cleanup operation are directly present in the patch.

## 4. Severity interpretation

This behaves like a Low-like or ordinary Moderate resource-lifetime cleanup issue, not an Important-class vulnerability. The theoretical impact is resource leakage if the failing initialization path is repeated, but the patch does not support UAF exploitation, attacker-controlled reclaim, object replacement, write-after-free, type confusion, or privilege escalation.

The realistic impact is limited availability degradation under privileged and hardware-specific conditions.

## 5. One-sentence report phrase

A host1x initialization error path used `kfree()` instead of `put_device()` after `device_initialize()`, causing a privileged local device-core reference leak with only theoretical DoS impact from repeated failures.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be auto-closed for most triage workflows because it is a privileged, hardware-specific reference leak without evidence of memory corruption, security-boundary bypass, or practical privilege escalation.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: gpu: host1x: Fix device reference leak in host1x_device_parse_dt() error path
Commit: a408d89e20d38d78f540e1951dc4c6056ad662e1
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a408d89e20d38d78f540e1951dc4c6056ad662e1

Commit description:

After device_initialize(), the embedded struct device in struct
host1x_device should be released through the device core with
put_device().

In host1x_device_add(), if host1x_device_parse_dt() fails, the current
error path frees the object directly with kfree(device). That bypasses
the normal device lifetime handling and leaks the reference held on the
embedded struct device.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fix this by using put_device() in the host1x_device_parse_dt() failure
path.

Fixes: f4c5cf8 ("gpu: host1x: Provide a proper struct bus_type")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Acked-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20260413141526.2961841-1-lgs201920130244@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/host1x/bus.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a408d89e20d38d78f540e1951dc4c6056ad662e1

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-72245 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72245

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.1

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 0
  Paranoid ActionableScore: 1

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).