From patchwork Wed Apr 17 05:16:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dixit, Ashutosh" X-Patchwork-Id: 13632876 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 23A0CC04FFE for ; Wed, 17 Apr 2024 05:16:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F1FBD11315F; Wed, 17 Apr 2024 05:16:49 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="bsjCIBSV"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7EAC4113155; Wed, 17 Apr 2024 05:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1713331009; x=1744867009; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=jtOytK7oWiptXH7Uo5vykc9AUFCufqIq7p1qkcmyN6c=; b=bsjCIBSVKV77MrjHHSnyfLtYuBOuvLM5uiZEGGFATCmnYcf0y05Ma9ld 5h63t20W1M3W1Q9X0VS79YFb61qd3FLividfj3boehL9Z9u1odIfkfw8R 0FigHu6bsqmKxGtYMONLFPC3PiU7x8YjwoY9t+DM24qtgzgMWDiqJ+CPx 8iLdjo2FFQ3pBg3JjN+knbZl1C4u0Ec7pJPzDQvWpOJ1x03QrntkbIZIH 6DPyM6XGuIrwHLrNZjEgmAlmRc4N8d97AkC12IHVEQe6vnG3sBBvjOKNV hePm3NoQwdn9BteH5C9ENkkKdp9Dj32qWdkeBXkp5i/nS2X1Zf2hwkfog g==; X-CSE-ConnectionGUID: jxGNjvJ8TNS2GSuGuL/u5Q== X-CSE-MsgGUID: hgG/4A12TUKKbgNQVMuLYQ== X-IronPort-AV: E=McAfee;i="6600,9927,11046"; a="31286423" X-IronPort-AV: E=Sophos;i="6.07,208,1708416000"; d="scan'208";a="31286423" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2024 22:16:48 -0700 X-CSE-ConnectionGUID: T8V37fKZRQaWYVN0MzdbKw== X-CSE-MsgGUID: 5h5+VWK+TjOfEYLKoAh/Xw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,208,1708416000"; d="scan'208";a="22570339" Received: from orsosgc001.jf.intel.com ([10.165.21.138]) by fmviesa010-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2024 22:16:47 -0700 From: Ashutosh Dixit To: intel-gfx@lists.freedesktop.org Cc: Badal Nilawar , Andi Shyti , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Rodrigo Vivi , Jani Nikula , linux-hwmon@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH v4] drm/i915/hwmon: Get rid of devm Date: Tue, 16 Apr 2024 22:16:42 -0700 Message-ID: <20240417051642.788740-1-ashutosh.dixit@intel.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" When both hwmon and hwmon drvdata (on which hwmon depends) are device managed resources, the expectation, on device unbind, is that hwmon will be released before drvdata. However, in i915 there are two separate code paths, which both release either drvdata or hwmon and either can be released before the other. These code paths (for device unbind) are as follows (see also the bug referenced below): Call Trace: release_nodes+0x11/0x70 devres_release_group+0xb2/0x110 component_unbind_all+0x8d/0xa0 component_del+0xa5/0x140 intel_pxp_tee_component_fini+0x29/0x40 [i915] intel_pxp_fini+0x33/0x80 [i915] i915_driver_remove+0x4c/0x120 [i915] i915_pci_remove+0x19/0x30 [i915] pci_device_remove+0x32/0xa0 device_release_driver_internal+0x19c/0x200 unbind_store+0x9c/0xb0 and Call Trace: release_nodes+0x11/0x70 devres_release_all+0x8a/0xc0 device_unbind_cleanup+0x9/0x70 device_release_driver_internal+0x1c1/0x200 unbind_store+0x9c/0xb0 This means that in i915, if use devm, we cannot gurantee that hwmon will always be released before drvdata. Which means that we have a uaf if hwmon sysfs is accessed when drvdata has been released but hwmon hasn't. The only way out of this seems to be do get rid of devm_ and release/free everything explicitly during device unbind. v2: Change commit message and other minor code changes v3: Cleanup from i915_hwmon_register on error (Armin Wolf) v4: Eliminate potential static analyzer warning (Rodrigo) Eliminate fetch_and_zero (Jani) Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10366 Reviewed-by: Rodrigo Vivi Signed-off-by: Ashutosh Dixit --- drivers/gpu/drm/i915/i915_hwmon.c | 52 +++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c index b758fd110c20..1551a40a675e 100644 --- a/drivers/gpu/drm/i915/i915_hwmon.c +++ b/drivers/gpu/drm/i915/i915_hwmon.c @@ -793,7 +793,7 @@ void i915_hwmon_register(struct drm_i915_private *i915) if (!IS_DGFX(i915)) return; - hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL); + hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL); if (!hwmon) return; @@ -819,14 +819,12 @@ void i915_hwmon_register(struct drm_i915_private *i915) hwm_get_preregistration_info(i915); /* hwmon_dev points to device hwmon */ - hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name, - ddat, - &hwm_chip_info, - hwm_groups); - if (IS_ERR(hwmon_dev)) { - i915->hwmon = NULL; - return; - } + hwmon_dev = hwmon_device_register_with_info(dev, ddat->name, + ddat, + &hwm_chip_info, + hwm_groups); + if (IS_ERR(hwmon_dev)) + goto err; ddat->hwmon_dev = hwmon_dev; @@ -839,16 +837,38 @@ void i915_hwmon_register(struct drm_i915_private *i915) if (!hwm_gt_is_visible(ddat_gt, hwmon_energy, hwmon_energy_input, 0)) continue; - hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat_gt->name, - ddat_gt, - &hwm_gt_chip_info, - NULL); - if (!IS_ERR(hwmon_dev)) - ddat_gt->hwmon_dev = hwmon_dev; + hwmon_dev = hwmon_device_register_with_info(dev, ddat_gt->name, + ddat_gt, + &hwm_gt_chip_info, + NULL); + if (IS_ERR(hwmon_dev)) + goto err; + + ddat_gt->hwmon_dev = hwmon_dev; } + return; +err: + i915_hwmon_unregister(i915); } void i915_hwmon_unregister(struct drm_i915_private *i915) { - fetch_and_zero(&i915->hwmon); + struct i915_hwmon *hwmon = i915->hwmon; + struct intel_gt *gt; + int i; + + if (!hwmon) + return; + + for_each_gt(gt, i915, i) + if (hwmon->ddat_gt[i].hwmon_dev) + hwmon_device_unregister(hwmon->ddat_gt[i].hwmon_dev); + + if (hwmon->ddat.hwmon_dev) + hwmon_device_unregister(hwmon->ddat.hwmon_dev); + + mutex_destroy(&hwmon->hwmon_lock); + + kfree(i915->hwmon); + i915->hwmon = NULL; }