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 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 D7609CD5BA4 for ; Wed, 20 May 2026 17:12:55 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E057E10E223; Wed, 20 May 2026 17:12:54 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MjVXT2Z1"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 48ADC10E223 for ; Wed, 20 May 2026 17:12:53 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id E273F4041B; Wed, 20 May 2026 17:12:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5889E1F000E9; Wed, 20 May 2026 17:12:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779297172; bh=uT5wMTCDA+xPSDJcEyj8k3m6s0Yt79U587ci3stT4Vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MjVXT2Z1wrep7OIsa82DLKPuLo1V+bdQf4LNqfA/yyt1BGfGWHJUFASw52k/j6jUb EetLxfMJfIkmbURkFeuFdQqRGl7FePmNbMSbRUHVmCKhzIs5rdF0AjtAMXrxGIy018 5993h2YZ17eEOu7tbG9QErsjI9lQOYw4fQSF9X4g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jatin Kataria , =?UTF-8?q?Christian=20K=C3=B6nig?= , Matthew Brost , dri-devel@lists.freedesktop.org, =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Boqun Feng Subject: [PATCH 7.0 1077/1146] drm/ttm: Fix ttm_bo_swapout() infinite LRU walk on swapout failure Date: Wed, 20 May 2026 18:22:07 +0200 Message-ID: <20260520162212.608402858@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162148.390695140@linuxfoundation.org> References: <20260520162148.390695140@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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" 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Hellström commit b2ed01e7ad3de80333e9b962a44024b094bc0b2b upstream. When ttm_tt_swapout() fails, the current code calls ttm_resource_add_bulk_move() followed by ttm_resource_move_to_lru_tail() to restore the resource's bulk_move membership. However, ttm_resource_move_to_lru_tail() places the resource at the tail of the LRU list which, relative to the walk cursor's hitch node (placed immediately after the resource when it was yielded), puts the resource *in front of the* the hitch. The next list_for_each_entry_continue() from the hitch finds the same resource again, causing an infinite loop. Fix by deferring del_bulk_move to the success path only. On the success path, TTM_TT_FLAG_SWAPPED has just been set by ttm_tt_swapout() but the resource is still tracked in the bulk_move range, so ttm_resource_del_bulk_move()'s !ttm_resource_unevictable() guard would incorrectly skip the removal. Introduce ttm_resource_del_bulk_move_unevictable() which bypasses that guard. Reported-by: Jatin Kataria Fixes: fc5d96670eb2 ("drm/ttm: Move swapped objects off the manager's LRU list") Cc: Christian König Cc: Matthew Brost Cc: Cc: # v6.13+ Assisted-by: GitHub_Copilot:claude-sonnet-4.6 Signed-off-by: Thomas Hellström Reviewed-by: Christian König Tested-by: Boqun Feng Link: https://patch.msgid.link/20260428094442.16985-1-thomas.hellstrom@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/ttm/ttm_bo.c | 16 ++++++---------- drivers/gpu/drm/ttm/ttm_resource.c | 13 +++++++++++++ include/drm/ttm/ttm_resource.h | 2 ++ 3 files changed, 21 insertions(+), 10 deletions(-) --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -1178,17 +1178,13 @@ ttm_bo_swapout_cb(struct ttm_lru_walk *w bdev->funcs->swap_notify(bo); if (ttm_tt_is_populated(tt)) { - spin_lock(&bdev->lru_lock); - ttm_resource_del_bulk_move(bo->resource, bo); - spin_unlock(&bdev->lru_lock); - ret = ttm_tt_swapout(bdev, tt, swapout_walk->gfp_flags); - - spin_lock(&bdev->lru_lock); - if (ret) - ttm_resource_add_bulk_move(bo->resource, bo); - ttm_resource_move_to_lru_tail(bo->resource); - spin_unlock(&bdev->lru_lock); + if (!ret) { + spin_lock(&bdev->lru_lock); + ttm_resource_del_bulk_move_unevictable(bo->resource, bo); + ttm_resource_move_to_lru_tail(bo->resource); + spin_unlock(&bdev->lru_lock); + } } out: --- a/drivers/gpu/drm/ttm/ttm_resource.c +++ b/drivers/gpu/drm/ttm/ttm_resource.c @@ -292,6 +292,19 @@ void ttm_resource_del_bulk_move(struct t ttm_lru_bulk_move_del(bo->bulk_move, res); } +/* + * Remove a resource from its bulk_move, bypassing the unevictable check. + * Use only when the resource is known to still be tracked in the range despite + * the BO having just become unevictable; asserts that this is the case. + */ +void ttm_resource_del_bulk_move_unevictable(struct ttm_resource *res, + struct ttm_buffer_object *bo) +{ + WARN_ON_ONCE(!ttm_resource_unevictable(res, bo)); + if (bo->bulk_move) + ttm_lru_bulk_move_del(bo->bulk_move, res); +} + /* Move a resource to the LRU or bulk tail */ void ttm_resource_move_to_lru_tail(struct ttm_resource *res) { --- a/include/drm/ttm/ttm_resource.h +++ b/include/drm/ttm/ttm_resource.h @@ -448,6 +448,8 @@ void ttm_resource_add_bulk_move(struct t struct ttm_buffer_object *bo); void ttm_resource_del_bulk_move(struct ttm_resource *res, struct ttm_buffer_object *bo); +void ttm_resource_del_bulk_move_unevictable(struct ttm_resource *res, + struct ttm_buffer_object *bo); void ttm_resource_move_to_lru_tail(struct ttm_resource *res); void ttm_resource_init(struct ttm_buffer_object *bo,