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 EB980E95A91 for ; Mon, 9 Oct 2023 09:00:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B420910E23B; Mon, 9 Oct 2023 09:00:59 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5163410E247 for ; Mon, 9 Oct 2023 09:00:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696842057; x=1728378057; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=j5MXRwDojiexnsWkL2vmC5YNlKy69DlXNGZEC7MCwWY=; b=QD/oHWnaQG6iR4Jgqz8jx5dwifmebtFp0nDwltOy/UBxG9ed6tuTv5qj 4Ro2vbHgoWXSJeg3X8lQMDO3pdyeghITeF/K2Ypw7Vl1ah/05tGsG1W1I 4LmGmb9ZBblgRF9a4pFS3Nk2YPx+5+Hu1g5lIXLpom0sdpLu5sHHHyTZa RnorvbkFB889o7Dl4KJ2P+oN6Ly3CestjGRImPjTLJ10ysA/A0EewtYg9 nwOzA0JsxlTELWKjPuhpF5JiLVVDfzPwMiK07MSZ3OEsB1bVav8MRcIMC NgzJklRC7+zoHGwNJMIw1QIIQLDSDbudanwgnF5NLobo5SiBmc+81ED1O g==; X-IronPort-AV: E=McAfee;i="6600,9927,10857"; a="382977038" X-IronPort-AV: E=Sophos;i="6.03,210,1694761200"; d="scan'208";a="382977038" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2023 02:00:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10857"; a="756647444" X-IronPort-AV: E=Sophos;i="6.03,210,1694761200"; d="scan'208";a="756647444" Received: from scusac1x-mobl.ger.corp.intel.com (HELO mwauld-mobl1.intel.com) ([10.252.31.166]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2023 02:00:54 -0700 From: Matthew Auld To: intel-xe@lists.freedesktop.org Date: Mon, 9 Oct 2023 10:00:38 +0100 Message-ID: <20231009090037.29132-2-matthew.auld@intel.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Intel-xe] [PATCH] drm/xe/bo: don't hold dma-resv lock over drm_gem_handle_create X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rodrigo Vivi Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" This seems to create a locking inversion with object_name_lock. The lock is held by drm_prime_fd_to_handle when calling our xe_gem_prime_import hook, which might eventually go on to grab the dma-resv lock during the attach. However we also have the opposite locking order in xe_gem_create_ioctl which is holding the dma-resv lock when calling drm_gem_handle_create, which wants to eventually grab object_name_lock: -> #1 (reservation_ww_class_mutex){+.+.}-{3:3}: <4> [635.739288] lock_acquire+0x169/0x3d0 <4> [635.739294] __ww_mutex_lock.constprop.0+0x164/0x1e60 <4> [635.739300] ww_mutex_lock_interruptible+0x42/0x1a0 <4> [635.739305] drm_gem_shmem_pin+0x4b/0x140 [drm_shmem_helper] <4> [635.739317] dma_buf_dynamic_attach+0x101/0x430 <4> [635.739323] xe_gem_prime_import+0xcc/0x2e0 [xe] <4> [635.739499] drm_prime_fd_to_handle_ioctl+0x184/0x2e0 [drm] <4> [635.739594] drm_ioctl_kernel+0x16f/0x250 [drm] <4> [635.739693] drm_ioctl+0x35e/0x620 [drm] <4> [635.739789] __x64_sys_ioctl+0xb7/0xf0 <4> [635.739794] do_syscall_64+0x3c/0x90 <4> [635.739799] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 <4> [635.739805] -> #0 (&dev->object_name_lock){+.+.}-{3:3}: <4> [635.739813] check_prev_add+0x1ba/0x14a0 <4> [635.739818] __lock_acquire+0x203e/0x2ff0 <4> [635.739823] lock_acquire+0x169/0x3d0 <4> [635.739827] __mutex_lock+0x124/0x1310 <4> [635.739832] drm_gem_handle_create+0x32/0x50 [drm] <4> [635.739927] xe_gem_create_ioctl+0x1d3/0x550 [xe] <4> [635.740102] drm_ioctl_kernel+0x16f/0x250 [drm] <4> [635.740197] drm_ioctl+0x35e/0x620 [drm] <4> [635.740293] __x64_sys_ioctl+0xb7/0xf0 <4> [635.740297] do_syscall_64+0x3c/0x90 <4> [635.740302] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 <4> [635.740307] It looks like it should be safe to simply drop the dma-resv lock prior to publishing the object when calling drm_gem_handle_create. Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/743 Signed-off-by: Matthew Auld Cc: Thomas Hellström Cc: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_bo.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c index 61789c0e88fb..ff116d3a8861 100644 --- a/drivers/gpu/drm/xe/xe_bo.c +++ b/drivers/gpu/drm/xe/xe_bo.c @@ -1815,14 +1815,16 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data, if (XE_IOCTL_DBG(xe, !vm)) return -ENOENT; err = xe_vm_lock(vm, true); - if (err) { - xe_vm_put(vm); - return err; - } + if (err) + goto out_vm; } bo = xe_bo_create(xe, NULL, vm, args->size, ttm_bo_type_device, bo_flags); + + if (vm) + xe_vm_unlock(vm); + if (IS_ERR(bo)) { err = PTR_ERR(bo); goto out_vm; @@ -1836,15 +1838,17 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data, goto out_put; out_bulk: - if (vm && !xe_vm_in_fault_mode(vm)) + if (vm && !xe_vm_in_fault_mode(vm)) { + xe_vm_lock(vm, false); __xe_bo_unset_bulk_move(bo); + xe_vm_unlock(vm); + } out_put: xe_bo_put(bo); out_vm: - if (vm) { - xe_vm_unlock(vm); + if (vm) xe_vm_put(vm); - } + return err; } -- 2.41.0