From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D7D9371D11 for ; Sat, 15 Aug 2026 06:23:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775005; cv=none; b=oVy9Bk8CciKZ/jkny0a1HMtGROqKzhxE5N4fGI10SXeBEJjnRLmpJ4cfLBx/WAB8jesw+mReC/544lCgg7TGESsF7FXHw5FU/SHLVlzjmkVL+pnCKp026ZrHM0+T/qM3KTyuSs9DuHPrIjtRFmBWGwej3GHVtP59eyBLReVj/H8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775005; c=relaxed/simple; bh=596dDZVzgFB7O3R9ur63ohtBzXsUNalRnQQ/iP88Xuo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XN0t40iR50umvzVy2m4M2rqZ0vuDO9pmDg20geI1eMNB6RWtYrZ76Rx8Outyyx5CV3ThndcubMtpUlW6fcXesGYlUqHsoaSssJfXQRlgCEXjIfooSdCxdDHF7yaymjGD2R4sPGptpAqowTACSQpHJ6hlbmXBDa+SSQDonkyjO+A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tN4nuFZQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tN4nuFZQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C91F81F000E9; Sat, 15 Aug 2026 06:23:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775004; bh=MQkqqgvL6Zata65lsw7zm6+arrWOzsFpmmq8ZvSlBp0=; h=From:To:Cc:Subject:Date:Reply-To; b=tN4nuFZQD9ni6m3m63w9/fJyv0AyFfiS/nz1eI/+kvIbyxmlfAEVLaC2xlPma2akT gX+CMy8obep5QI2GVnI6WOM8IHSCeLzBjYNlskiKjLQQ8Xd6dGuWJumMjwo638bz+f EOyBHhFD6Zfknj5zzu+YinaEXc4Hsn/BsbYx8jtY= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-72342: net/mlx5e: Fix HV VHCA stats agent registration race Date: Sat, 15 Aug 2026 15:07:01 +0900 Message-ID: <2026081510-CVE-2026-72342-0fc2@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5314; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=KuITm1JjNRwdrh6TTcWvDAZuAIa/BsTuH4DvBE5UWEU=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNDI+6HFcKfsz9lto47ZH4pYB9K1YynFHwvb/bumPaX fOWqPIdHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRjYsZFpxi3J9Zznok+esB 84pjfhLeupd91RgWrNU4JH3zJ3fM+qenJlTXP/N1ZHI5CQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In 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. The Linux kernel CVE team has assigned CVE-2026-72342 to this issue. Affected and fixed versions =========================== Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 6.1.178 with commit b0fd6d3bb06182f19f3b59a53f57b5098b99048a Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 6.6.145 with commit 24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 6.12.97 with commit e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5 Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 6.18.40 with commit 60fddda7207d81fea71463abd403f0b10f74f2e1 Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 7.1.5 with commit f5677797b094c3ec5fb350eb8ea7710b88a3d018 Issue introduced in 5.4 with commit cef35af34d6dc3792333075115c7deb7062b6e18 and fixed in 7.2-rc3 with commit 89b25b5f46f488ea3b29b3444864c76944c9075b 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-2026-72342 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/mellanox/mlx5/core/en/hv_vhca_stats.c drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.c drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.h 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/b0fd6d3bb06182f19f3b59a53f57b5098b99048a https://git.kernel.org/stable/c/24c77044cdfcf5b8b2e9f3b620d8b9aa392d9add https://git.kernel.org/stable/c/e8fc3304cb67fb1d7d11ff9ef9abd5fb64e7e1d5 https://git.kernel.org/stable/c/60fddda7207d81fea71463abd403f0b10f74f2e1 https://git.kernel.org/stable/c/f5677797b094c3ec5fb350eb8ea7710b88a3d018 https://git.kernel.org/stable/c/89b25b5f46f488ea3b29b3444864c76944c9075b