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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 251D3C433EF for ; Fri, 24 Sep 2021 13:04:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 107A3610CB for ; Fri, 24 Sep 2021 13:04:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346311AbhIXNFe (ORCPT ); Fri, 24 Sep 2021 09:05:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:33118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346177AbhIXNDB (ORCPT ); Fri, 24 Sep 2021 09:03:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BDD8161378; Fri, 24 Sep 2021 12:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632488096; bh=jVCPuOo7/RvvFyuQRc2h4nEhQuGVZQvPPxT5ZpCDdQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IL1DebVpppv3EsA4N0clJGnYKPCGXQPHHHjHZJV0QjiMOOQR1qmdXwai56P7glF+r tkcrTLzhZMh8yOG6iWbjSpT9n9HSNNq2vV14CQg4Zxm45jf08ncG9pUnNScss6CgQv tQq1HVcFmyDau4+bEOEpScEA+rj4+JCUQGBQ15Lo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Philip Yang , Felix Kuehling , Alex Deucher , Sasha Levin Subject: [PATCH 5.14 083/100] drm/amdgpu: fix fdinfo race with process exit Date: Fri, 24 Sep 2021 14:44:32 +0200 Message-Id: <20210924124344.247941751@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210924124341.214446495@linuxfoundation.org> References: <20210924124341.214446495@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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); -- 2.33.0