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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 2A258C4332F for ; Fri, 17 Sep 2021 02:34:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 100A0610C8 for ; Fri, 17 Sep 2021 02:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242888AbhIQCfb (ORCPT ); Thu, 16 Sep 2021 22:35:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:60898 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242869AbhIQCfT (ORCPT ); Thu, 16 Sep 2021 22:35:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7932C610C8; Fri, 17 Sep 2021 02:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631846037; bh=yL0/A3pixD015Ittns9985y2gTKx7hLj4leP8ysqkSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KHPLj8sb0vJSXWERy7B1NTdWegyKD6VqOsPB7KZVQrJTCvUwx3uP7uiCAh/xrArg6 zkBLvW2bdMo7q5mBCB5IeZSjSRcARK6JNB2AN4KKNQsu6oLAZlI5Oew/Ma3tE1Ejjj p74IjrKhm9y4qPQsa33SPz7bJhvVAbodrrxkAgmRTqhDvAq2EVMQoNM0HKrVei53gX /vRDVquzGsqPZI5lKtYj/+7pfQv/X9X1pqvvt4hSpqTm9N7fVoSrIMB0L1+EGgUQTm EpUkDDYxeN89QvmOz8WTdufBXx1IOXPYHBwbRdz6H/yd5dL2SO+xS9oXzQpGd8WGEG 2Ya+rSb+xhqIg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Philip Yang , Felix Kuehling , Alex Deucher , Sasha Levin , christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@linux.ie, daniel@ffwll.ch, Roy.Sun@amd.com, nirmoy.das@amd.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.14 06/21] drm/amdgpu: fix fdinfo race with process exit Date: Thu, 16 Sep 2021 22:33:00 -0400 Message-Id: <20210917023315.816225-6-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210917023315.816225-1-sashal@kernel.org> References: <20210917023315.816225-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Philip Yang [ Upstream commit d7eff46c214c036606dd3cd305bd5a128aecfe8c ] Get process vm root BO ref in case process is exiting and root BO is freed, to avoid NULL pointer dereference backtrace: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 Call Trace: amdgpu_show_fdinfo+0xfe/0x2a0 [amdgpu] seq_show+0x12c/0x180 seq_read+0x153/0x410 vfs_read+0x91/0x140[ 3427.206183] ksys_read+0x4f/0xb0 do_syscall_64+0x5b/0x1a0 entry_SYSCALL_64_after_hwframe+0x65/0xca Signed-off-by: Philip Yang Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c index d94c5419ec25..5a6857c44bb6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c @@ -59,6 +59,7 @@ void amdgpu_show_fdinfo(struct seq_file *m, struct file *f) uint64_t vram_mem = 0, gtt_mem = 0, cpu_mem = 0; struct drm_file *file = f->private_data; struct amdgpu_device *adev = drm_to_adev(file->minor->dev); + struct amdgpu_bo *root; int ret; ret = amdgpu_file_to_fpriv(f, &fpriv); @@ -69,13 +70,19 @@ void amdgpu_show_fdinfo(struct seq_file *m, struct file *f) dev = PCI_SLOT(adev->pdev->devfn); fn = PCI_FUNC(adev->pdev->devfn); - ret = amdgpu_bo_reserve(fpriv->vm.root.bo, false); + root = amdgpu_bo_ref(fpriv->vm.root.bo); + if (!root) + return; + + ret = amdgpu_bo_reserve(root, false); if (ret) { DRM_ERROR("Fail to reserve bo\n"); return; } amdgpu_vm_get_memory(&fpriv->vm, &vram_mem, >t_mem, &cpu_mem); - amdgpu_bo_unreserve(fpriv->vm.root.bo); + amdgpu_bo_unreserve(root); + amdgpu_bo_unref(&root); + seq_printf(m, "pdev:\t%04x:%02x:%02x.%d\npasid:\t%u\n", domain, bus, dev, fn, fpriv->vm.pasid); seq_printf(m, "vram mem:\t%llu kB\n", vram_mem/1024UL); -- 2.30.2