From patchwork Tue Oct 27 21:49:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11861941 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 728ED921 for ; Tue, 27 Oct 2020 21:49:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48472207E8 for ; Tue, 27 Oct 2020 21:49:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="aRDyobZ7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S374456AbgJ0Vtm (ORCPT ); Tue, 27 Oct 2020 17:49:42 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:34181 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S374454AbgJ0Vtm (ORCPT ); Tue, 27 Oct 2020 17:49:42 -0400 Received: by mail-wm1-f66.google.com with SMTP id k21so1962461wmi.1 for ; Tue, 27 Oct 2020 14:49:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=V8no5NLx/EPXeK3IR/DnmSVtE8r9cF0bSgSu8ZLPdMw=; b=aRDyobZ7krZL7Pf7BVzo8QG2FDxcmJ9CXt4MjKL+s/67M3acWl0aexo7kZUXiyHG1e ft6UrfT8UxfndswEBrXy8J3WJNnkao3SGzh9zQSFQP9xQCs09ullxZIeAvJ0mD/Q983a QsKRhHKdvA78dAun2cI/4M1yS3ykh8QDJAwI8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=V8no5NLx/EPXeK3IR/DnmSVtE8r9cF0bSgSu8ZLPdMw=; b=AWj+sBXYvoTPScagJJ7Kp9sHefZUCsj8s6Lxfi/arDDdDNXZoW4DKka6uJYzPke7Kn D2Z3e2lTMNsWN+vZ6Q3073zGjlXt0TuYH8fF2jHFqauVqy0UdR7GhLGEEaGiyemJDT4P rJA8bHLimvv4Nlpy9tKc+I9QQW+/GLzuQ+247lNzYzBf7avyXlHU/3BdwhlagPwk3eOt bT5TiRKueLWb1me4h551dpqKP4j6PX1XWWSbArdsK6V1dJj3yNoH2m93qz3s8fWX4vVT ZN+NIOqLXMtNwA1x/f+mBz8Qt/A1d/c4/f9Z0KLMVrlCUaezg50pVz2MPoNiPTbwRlLC xXjw== X-Gm-Message-State: AOAM532Za2R+oqD/86pkG0lgsk2ARuuG5MRWrAM1qKEBqQh2YzPvXyCD Kna54rymsERjmhiv/vRh8Ju0Qw== X-Google-Smtp-Source: ABdhPJxbLJNJ+DNsc2Vj5AgNJFuMtAN0kc4/8NmFGgYnXE7uZIMveSFMusf90xuHdaxHEKHu608YJw== X-Received: by 2002:a05:600c:21c3:: with SMTP id x3mr4653420wmj.81.1603835378528; Tue, 27 Oct 2020 14:49:38 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id e11sm3444488wrj.75.2020.10.27.14.49.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 14:49:37 -0700 (PDT) From: Daniel Vetter To: DRI Development Cc: Daniel Vetter , =?utf-8?q?Christian_K=C3=B6nig?= , Sumit Semwal , Lucas Stach , Russell King , Christian Gmeiner , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Boris Brezillon , Thomas Zimmermann , Gerd Hoffmann , Rob Herring , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, stable@vger.kernel.org, piotr.oniszczuk@gmail.com, Daniel Vetter Subject: [PATCH] drm/shme-helpers: Fix dma_buf_mmap forwarding bug Date: Tue, 27 Oct 2020 22:49:22 +0100 Message-Id: <20201027214922.3566743-1-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org When we forward an mmap to the dma_buf exporter, they get to own everything. Unfortunately drm_gem_mmap_obj() overwrote vma->vm_private_data after the driver callback, wreaking the exporter complete. This was noticed because vb2_common_vm_close blew up on mali gpu with panfrost after commit 26d3ac3cb04d ("drm/shmem-helpers: Redirect mmap for imported dma-buf"). Unfortunately drm_gem_mmap_obj also acquires a surplus reference that we need to drop in shmem helpers, which is a bit of a mislayer situation. Maybe the entire dma_buf_mmap forwarding should be pulled into core gem code. Note that the only two other drivers which forward mmap in their own code (etnaviv and exynos) get this somewhat right by overwriting the gem mmap code. But they seem to still have the leak. This might be a good excuse to move these drivers over to shmem helpers completely. Note to stable team: There's a trivial context conflict with d693def4fd1c ("drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver"). I'm assuming it's clear where to put the first hunk, otherwise I can send a 5.9 version of this. Cc: Christian König Cc: Sumit Semwal Cc: Lucas Stach Cc: Russell King Cc: Christian Gmeiner Cc: Inki Dae Cc: Joonyoung Shim Cc: Seung-Woo Kim Cc: Kyungmin Park Fixes: 26d3ac3cb04d ("drm/shmem-helpers: Redirect mmap for imported dma-buf") Cc: Boris Brezillon Cc: Thomas Zimmermann Cc: Gerd Hoffmann Cc: Rob Herring Cc: dri-devel@lists.freedesktop.org Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Cc: # v5.9+ Reported-and-tested-by: piotr.oniszczuk@gmail.com Cc: piotr.oniszczuk@gmail.com Signed-off-by: Daniel Vetter Reviewed-by: Boris Brezillon Acked-by: Christian König --- drivers/gpu/drm/drm_gem.c | 4 ++-- drivers/gpu/drm/drm_gem_shmem_helper.c | 7 ++++++- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 1da67d34e55d..d586068f5509 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -1076,6 +1076,8 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, */ drm_gem_object_get(obj); + vma->vm_private_data = obj; + if (obj->funcs->mmap) { ret = obj->funcs->mmap(obj, vma); if (ret) { @@ -1096,8 +1098,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); } - vma->vm_private_data = obj; - return 0; } EXPORT_SYMBOL(drm_gem_mmap_obj); diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index fb11df7aced5..8233bda4692f 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -598,8 +598,13 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) /* Remove the fake offset */ vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); - if (obj->import_attach) + if (obj->import_attach) { + /* Drop the reference drm_gem_mmap_obj() acquired.*/ + drm_gem_object_put(obj); + vma->vm_private_data = NULL; + return dma_buf_mmap(obj->dma_buf, vma, 0); + } shmem = to_drm_gem_shmem_obj(obj);