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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3B88C48BD1 for ; Fri, 11 Jun 2021 18:23:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D28A7613D9 for ; Fri, 11 Jun 2021 18:23:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231264AbhFKSZO convert rfc822-to-8bit (ORCPT ); Fri, 11 Jun 2021 14:25:14 -0400 Received: from hosting.gsystem.sk ([212.5.213.30]:51094 "EHLO hosting.gsystem.sk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231209AbhFKSZN (ORCPT ); Fri, 11 Jun 2021 14:25:13 -0400 Received: from [192.168.0.2] (unknown [188.167.68.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by hosting.gsystem.sk (Postfix) with ESMTPSA id F2EDD7A024A; Fri, 11 Jun 2021 20:23:13 +0200 (CEST) From: Ondrej Zary To: Christian =?utf-8?q?K=C3=B6nig?= Subject: Re: nouveau broken on Riva TNT2 in 5.13.0-rc4: NULL pointer dereference in nouveau_bo_sync_for_device Date: Fri, 11 Jun 2021 20:23:10 +0200 User-Agent: KMail/1.9.10 Cc: Ben Skeggs , dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <202106052143.52488.linux@zary.sk> <4b4248d8-b708-3832-7fe3-2a9fd2c2311e@amd.com> In-Reply-To: <4b4248d8-b708-3832-7fe3-2a9fd2c2311e@amd.com> X-KMail-QuotePrefix: > MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <202106112023.11270.linux@zary.sk> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 11 June 2021 14:38:18 Christian König wrote: > > Am 10.06.21 um 19:59 schrieb Christian König: > > Am 10.06.21 um 19:50 schrieb Ondrej Zary: > >> [SNIP] > >>> I can't see how this is called from the nouveau code, only > >>> possibility I > >>> see is that it is maybe called through the AGP code somehow. > >> Yes, you're right: > >> [   13.192663] Call Trace: > >> [   13.192678]  dump_stack+0x54/0x68 > >> [   13.192690]  ttm_tt_init+0x11/0x8a [ttm] > >> [   13.192699]  ttm_agp_tt_create+0x39/0x51 [ttm] > >> [   13.192840]  nouveau_ttm_tt_create+0x17/0x22 [nouveau] > >> [   13.192856]  ttm_tt_create+0x78/0x8c [ttm] > >> [   13.192864]  ttm_bo_handle_move_mem+0x7d/0xca [ttm] > >> [   13.192873]  ttm_bo_validate+0x92/0xc8 [ttm] > >> [   13.192883]  ttm_bo_init_reserved+0x216/0x243 [ttm] > >> [   13.192892]  ttm_bo_init+0x45/0x65 [ttm] > >> [   13.193018]  ? nouveau_bo_del_io_reserve_lru+0x48/0x48 [nouveau] > >> [   13.193150]  nouveau_bo_init+0x8c/0x94 [nouveau] > >> [   13.193273]  ? nouveau_bo_del_io_reserve_lru+0x48/0x48 [nouveau] > >> [   13.193407]  nouveau_bo_new+0x44/0x57 [nouveau] > >> [   13.193537]  nouveau_channel_prep+0xa3/0x269 [nouveau] > >> [   13.193665]  nouveau_channel_new+0x3c/0x5f7 [nouveau] > >> [   13.193679]  ? slab_free_freelist_hook+0x3b/0xa7 > >> [   13.193686]  ? kfree+0x9e/0x11a > >> [   13.193781]  ? nvif_object_sclass_put+0xd/0x16 [nouveau] > >> [   13.193908]  nouveau_drm_device_init+0x2e2/0x646 [nouveau] > >> [   13.193924]  ? pci_enable_device_flags+0x1e/0xac > >> [   13.194052]  nouveau_drm_probe+0xeb/0x188 [nouveau] > >> [   13.194182]  ? nouveau_drm_device_init+0x646/0x646 [nouveau] > >> [   13.194195]  pci_device_probe+0x89/0xe9 > >> [   13.194205]  really_probe+0x127/0x2a7 > >> [   13.194212]  driver_probe_device+0x5b/0x87 > >> [   13.194219]  device_driver_attach+0x2e/0x41 > >> [   13.194226]  __driver_attach+0x7c/0x83 > >> [   13.194232]  bus_for_each_dev+0x4c/0x66 > >> [   13.194238]  driver_attach+0x14/0x16 > >> [   13.194244]  ? device_driver_attach+0x41/0x41 > >> [   13.194251]  bus_add_driver+0xc5/0x16c > >> [   13.194258]  driver_register+0x87/0xb9 > >> [   13.194265]  __pci_register_driver+0x38/0x3b > >> [   13.194271]  ? 0xf0c0d000 > >> [   13.194362]  nouveau_drm_init+0x14c/0x1000 [nouveau] > >> > >> How is ttm_dma_tt->dma_address allocated? > > > > Mhm, I need to double check how AGP is supposed to work. > > > > Since barely anybody is using it these days it is something which > > breaks from time to time. > > I have no idea how that ever worked in the first place since AGP isn't > supposed to sync between CPU/GPU. Everything is coherent for that case. > > Anyway here is a patch which adds a check to those functions if the > dma_address array is allocated in the first place. Please test it. Thanks, the patch fixes the problem and nouveau now works! Should be applied to 5.12-stable too (5.11 is affected too but EOL). It's weird that it worked before. Looks like dma_address was used uninitialized - it contained some random crap: [ 12.293304] nouveau_bo_sync_for_device: ttm_dma->dma_address=3e055971 ttm_dma->ttm.num_pages=18 [ 12.293321] ttm_dma->dma_address[0]=0x0 [ 12.293341] ttm_dma->dma_address[1]=0x0 [ 12.293360] ttm_dma->dma_address[2]=0xee728980 [ 12.293379] ttm_dma->dma_address[3]=0xed1cb120 [ 12.293397] ttm_dma->dma_address[4]=0x12 [ 12.293416] ttm_dma->dma_address[5]=0x0 [ 12.293434] ttm_dma->dma_address[6]=0x1 [ 12.293453] ttm_dma->dma_address[7]=0x0 [ 12.293471] ttm_dma->dma_address[8]=0x10000 [ 12.293490] ttm_dma->dma_address[9]=0x0 [ 12.293510] ttm_dma->dma_address[10]=0x101 [ 12.293528] ttm_dma->dma_address[11]=0xee7289ec [ 12.293546] ttm_dma->dma_address[12]=0xee7289ec [ 12.293564] ttm_dma->dma_address[13]=0x0 [ 12.293581] ttm_dma->dma_address[14]=0x0 [ 12.293599] ttm_dma->dma_address[15]=0x0 [ 12.293616] ttm_dma->dma_address[16]=0x0 [ 12.293634] ttm_dma->dma_address[17]=0x0 But it did not matter as dma_sync_single_for_device is a no-op here. When dma_address is properly initialized to NULL, it crashes... > Thanks, > Christian. > > > > > Thanks for the backtrace, > > Christian. > > > >>   I cannot find any assignment > >> executed (in the working code): > >> > >> $ git grep dma_address\ = drivers/gpu/ > >> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c: > >> sg->sgl->dma_address = addr; > >> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c: dma_address = > >> &dma->dma_address[offset >> PAGE_SHIFT]; > >> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c: dma_address = > >> (mm_node->start << PAGE_SHIFT) + offset; > >> drivers/gpu/drm/i915/gvt/scheduler.c:   sg->dma_address = addr; > >> drivers/gpu/drm/i915/i915_gpu_error.c:  sg->dma_address = it; > >> drivers/gpu/drm/ttm/ttm_tt.c:   ttm->dma_address = (void *) > >> (ttm->ttm.pages + ttm->ttm.num_pages); > >> drivers/gpu/drm/ttm/ttm_tt.c:   ttm->dma_address = > >> kvmalloc_array(ttm->ttm.num_pages, > >> drivers/gpu/drm/ttm/ttm_tt.c:   ttm_dma->dma_address = NULL; > >> drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c: viter->dma_address = > >> &__vmw_piter_phys_addr; > >> drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c: viter->dma_address = > >> &__vmw_piter_dma_addr; > >> drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c: viter->dma_address = > >> &__vmw_piter_sg_addr; > >> > >> The 2 cases in ttm_tt.c are in ttm_dma_tt_alloc_page_directory() and > >> ttm_sg_tt_alloc_page_directory(). > >> Confirmed by adding printk()s that they're NOT called. > >> > >> > > > > -- Ondrej Zary