From patchwork Tue Mar 7 14:46:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Hellstrom X-Patchwork-Id: 13163845 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 31182C678D4 for ; Tue, 7 Mar 2023 14:47:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F060110E4CB; Tue, 7 Mar 2023 14:47:10 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 307CC10E4C9; Tue, 7 Mar 2023 14:47:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678200429; x=1709736429; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=oazg6p2WalywNNv6pSy0F8qJWnEkCQHXKwMG7qicgxo=; b=htfGZYVWPOLRm2pqvfHADXlK64cO8zixXlnUrcCWJhLD8qIBNqbFkYa0 7GAPMHvAABd+KLkXXG+3YnQhX+1FbU5YmJIVfuZlzs7gi0VO53BFDZMUL 4n9GRDf9PZiKuw2XEjn77FBzTxAFAMLmOlgn2rIlocbX0NqbC9NMBxDFm +Nm5/OlkWEGYvD0L/icta+uN11OdV14SXTa5T9i4dn9W4wTlq5KBZQUJT RrgmHSQWM4rvchf6PLrLQy5zYu5omYqUk1iKyS+oyon2m+GgOgPXzKCDj mFe3r4HwMyyOux6axan1IotlBF/2gsSIWQJs+srboC9N3DI4b+8LlimUL g==; X-IronPort-AV: E=McAfee;i="6500,9779,10642"; a="400687216" X-IronPort-AV: E=Sophos;i="5.98,241,1673942400"; d="scan'208";a="400687216" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2023 06:47:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10642"; a="800414348" X-IronPort-AV: E=Sophos;i="5.98,241,1673942400"; d="scan'208";a="800414348" Received: from peiwangc-mobl1.ccr.corp.intel.com (HELO thellstr-mobl1.intel.com) ([10.249.254.10]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2023 06:47:04 -0800 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: dri-devel@lists.freedesktop.org Date: Tue, 7 Mar 2023 15:46:15 +0100 Message-Id: <20230307144621.10748-2-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307144621.10748-1-thomas.hellstrom@linux.intel.com> References: <20230307144621.10748-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v2 1/7] drm/ttm: Fix a NULL pointer dereference X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?q?Thomas_Hellstr=C3=B6m?= , Arunpravin Paneer Selvam , Philip Yang , Daniel Vetter , Felix Kuehling , Qiang Yu , Huang Rui , Matthew Auld , Alex Deucher , intel-gfx@lists.freedesktop.org, =?utf-8?q?Christian_K=C3=B6nig?= , Nirmoy Das Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The LRU mechanism may look up a resource in the process of being removed from an object. The locking rules here are a bit unclear but it looks currently like res->bo assignment is protected by the LRU lock, whereas bo->resource is protected by the object lock, while *clearing* of bo->resource is also protected by the LRU lock. This means that if we check that bo->resource points to the LRU resource under the LRU lock we should be safe. So perform that check before deciding to swap out a bo. That avoids dereferencing a NULL bo->resource in ttm_bo_swapout(). Fixes: 6a9b02899402 ("drm/ttm: move the LRU into resource handling v4") Cc: Christian König Cc: Daniel Vetter Cc: Christian Koenig Cc: Huang Rui Cc: Alex Deucher Cc: Felix Kuehling Cc: Philip Yang Cc: Qiang Yu Cc: Matthew Auld Cc: Nirmoy Das Cc: Tvrtko Ursulin Cc: "Thomas Hellström" Cc: Anshuman Gupta Cc: Arunpravin Paneer Selvam Cc: dri-devel@lists.freedesktop.org Signed-off-by: Thomas Hellström Reviewed-by: Christian König --- drivers/gpu/drm/ttm/ttm_device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c index c7a1862f322a..ae2f19dc9f81 100644 --- a/drivers/gpu/drm/ttm/ttm_device.c +++ b/drivers/gpu/drm/ttm/ttm_device.c @@ -158,7 +158,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo = res->bo; uint32_t num_pages; - if (!bo) + if (!bo || bo->resource != res) continue; num_pages = PFN_UP(bo->base.size);