net/mlx5e: Fix HV VHCA stats agent registration race

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72342
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:07 UTC
Updated2026-08-17 06:18:38 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats agent registration race mlx5e_hv_vhca_stats_create() registers the stats agent through mlx5_hv_vhca_agent_create(). The helper publishes the agent in hv_vhca->agents[type] under agents_lock and immediately schedules an asynchronous control invalidation on the HV VHCA workqueue before returning to mlx5e. The asynchronous invalidation invokes the control agent's invalidate callback, which reads the hypervisor control block and forwards the command to mlx5e_hv_vhca_stats_control(). That callback may either: - call cancel_delayed_work_sync(&priv->stats_agent.work), or - call queue_delayed_work(priv->wq, &sagent->work, sagent->delay). However, the delayed_work and priv->stats_agent.agent are only initialized after mlx5_hv_vhca_agent_create() returns to mlx5e: agent = mlx5_hv_vhca_agent_create(...); /* publish + invalidate */ ... priv->stats_agent.agent = agent; /* too late */ INIT_DELAYED_WORK(&priv->stats_agent.work, ...); /* too late */ If the asynchronous control path runs before the two assignments above, it can: - Operate on an uninitialized delayed_work whose timer.function is NULL. queue_delayed_work() calls add_timer() unconditionally, so when the timer expires the timer softirq invokes a NULL function pointer. - Re-initialize the timer later through INIT_DELAYED_WORK() while the timer is already enqueued in the timer wheel, corrupting the hlist (entry.pprev cleared while the previous bucket node still points at this entry). - When the worker eventually runs, mlx5e_hv_vhca_stats_work() reads sagent->agent (NULL) and dereferences it inside mlx5_hv_vhca_agent_write(). Fix this by: - Initializing priv->stats_agent.work before invoking mlx5_hv_vhca_agent_create(), so the work is always in a valid state when the control callback observes it. - Adding a struct mlx5_hv_vhca_agent **ctx_update out-parameter to mlx5_hv_vhca_agent_create(). The helper writes the agent pointer to *ctx_update before publishing into hv_vhca->agents[] and triggering the agents_update flow, so any callback subsequently invoked from that flow already sees a valid priv->stats_agent.agent. This avoids having the control callback participate in agent initialization. While at it, access priv->stats_agent.agent with READ_ONCE()/WRITE_ONCE() for the cross-CPU access with the worker, and clear priv->stats_agent.buf on the agent_create() failure path.

Risk And Classification

Primary CVSS: v3.1 8.4 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001930000 probability, percentile 0.093310000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.4HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.4HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 b0fd6d3bb06182f19f3b59a53f57b5098b99048a git Not specified
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add git Not specified
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5 git Not specified
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 60fddda7207d81fea71463abd403f0b10f74f2e1 git Not specified
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 f5677797b094c3ec5fb350eb8ea7710b88a3d018 git Not specified
CNA Linux Linux affected cef35af34d6dc3792333075115c7deb7062b6e18 89b25b5f46f488ea3b29b3444864c76944c9075b git Not specified
CNA Linux Linux affected 5.4 Not specified
CNA Linux Linux unaffected 5.4 semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f5677797b094c3ec5fb350eb8ea7710b88a3d018 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/89b25b5f46f488ea3b29b3444864c76944c9075b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b0fd6d3bb06182f19f3b59a53f57b5098b99048a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/60fddda7207d81fea71463abd403f0b10f74f2e1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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