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 3BFB749DB99; Wed, 23 Sep 2026 14:20:36 +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=1790173237; cv=none; b=Y9+RwxlKyDz/tMOPNBcEFdxbL+pbLKR1SxvmRMjizt5LY8oBiEyW5/+8GCgfA9XgTug9C53KPSWBbNOvmplpXHcnMu9IUgYSNdV6iDNqNCKNV98kUXk4aYlg3b6K/CgrTtY/9Hww6dPFoXjI6zZbRtKTPwcwT1lV45C4hwnxeYY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790173237; c=relaxed/simple; bh=Dhp2HumRnTXc5UwazAZvoT/9pZzbPfaa2tXBe3YwPP0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jNL9sMzf+suX6MHviBGk3Ufvm3VbXOls/V+5eb2XBSfhGz186Phh4dzNrfwiAO5sCFQZlmWjO3oyE//65RzyrBOAcvS6pfgrWOjl9PySSPqn/V3YMKYJdWG6KtDm4MpsZLPDVObP2QRQh89s0c7VhwiiAiIOCGoEjTXRd6i+wFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fOpXQzbz; 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="fOpXQzbz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67FBD1F000FF; Wed, 23 Sep 2026 14:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790173236; bh=FOm347BktZwO+YYbtGj4Vwso2RsgO3PiKpF/HWjP3jo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fOpXQzbzH3bwnLeYgdoVPJtHAVl9KJJ7TwBYU5cXVlndVKRePwrGbVPMn+6Fg9sNg wVCkqBXRyhEY1Zu5ot/239btHB5Cnq5w4/tFi44Zj/V7HbRaYBjhAnd/N9kZPZCmaF s7m1mfPiJVteAssXD/FodkoNV9GK4iqD9edtaJPo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , =?UTF-8?q?Ma=C3=ADra=20Canal?= , Sasha Levin Subject: [PATCH 7.2 149/438] drm/vc4: Use managed KMS polling to fix UAF on unbind Date: Wed, 23 Sep 2026 16:02:50 +0200 Message-ID: <20260923140648.633629835@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140644.756254324@linuxfoundation.org> References: <20260923140644.756254324@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter [ Upstream commit 073a30d75f309812ed61af134f24ffef4107b13a ] vc4_kms_load() calls drm_kms_helper_poll_init() but the driver provides no matching drm_kms_helper_poll_fini(). The output poll work stays scheduled after unbind and runs on the freed drm_device: # modprobe vc4; rmmod vc4; sleep 10 BUG: KASAN: slab-use-after-free in delayed_work_timer_fn BUG: KASAN: slab-use-after-free in drm_client_dev_hotplug [drm] Workqueue: events output_poll_execute [drm_kms_helper] Allocated by task 171: __devm_drm_dev_alloc Freed by task 262 (rmmod): drm_dev_put / component_del Use drmm_kms_helper_poll_init() so polling is finalized with the device, as other drivers do. Fixes: c8b75bca92cb ("drm/vc4: Add KMS support for Raspberry Pi.") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Link: https://patch.msgid.link/20260822143110.68594-1-kmehltretter@gmail.com Reviewed-by: Maíra Canal Signed-off-by: Maíra Canal Signed-off-by: Sasha Levin --- drivers/gpu/drm/vc4/vc4_kms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index b17e73bce3841..82a7f2ac4c7e2 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -1188,7 +1188,7 @@ int vc4_kms_load(struct drm_device *dev) drm_mode_config_reset(dev); - drm_kms_helper_poll_init(dev); + drmm_kms_helper_poll_init(dev); return 0; } -- 2.53.0