From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DB72C6FD1D for ; Mon, 20 Mar 2023 15:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233085AbjCTPbr (ORCPT ); Mon, 20 Mar 2023 11:31:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232839AbjCTPb2 (ORCPT ); Mon, 20 Mar 2023 11:31:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D823734020 for ; Mon, 20 Mar 2023 08:23:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0C97FB80E55 for ; Mon, 20 Mar 2023 15:23:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 328C4C4339C; Mon, 20 Mar 2023 15:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1679325827; bh=SfCZawwhNVkHFA9/sY9LZNRj6mtwDsVyCSJo6iC8ZxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R+kRlSBM027emes+TDJwlRfWMAzqt8y0XSLiJY0ujgljnASz9gmo9/n/1BvN+dvhW 2sIs/TlzQCquh9uL9eDjSBHhqR6yg/vMnW3vJ5cXbWbj0QJhjFdiT9srcVK1frQ7iu UnXqhSFNXarCLgj1BIOPBWALwxdxSyuxOgt35pzI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Christian=20K=C3=B6nig?= , Daniel Vetter , Huang Rui , Alex Deucher , Felix Kuehling , Philip Yang , Qiang Yu , Matthew Auld , Nirmoy Das , Tvrtko Ursulin , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Anshuman Gupta , Arunpravin Paneer Selvam , dri-devel@lists.freedesktop.org Subject: [PATCH 6.1 127/198] drm/ttm: Fix a NULL pointer dereference Date: Mon, 20 Mar 2023 15:54:25 +0100 Message-Id: <20230320145512.868867333@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230320145507.420176832@linuxfoundation.org> References: <20230320145507.420176832@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Hellström commit 9a9a8fe26751334b7739193a94eba741073b8a55 upstream. 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 Cc: # v5.19+ Signed-off-by: Thomas Hellström Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20230307144621.10748-2-thomas.hellstrom@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- 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 e7147e304637..b84f74807ca1 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); -- 2.40.0