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 3E873C79F80 for ; Fri, 4 Sep 2026 07:23:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E47E010F8E2; Fri, 4 Sep 2026 07:23:07 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Kw6WeiY9"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) by gabe.freedesktop.org (Postfix) with ESMTPS id 46EC510F8C7 for ; Fri, 4 Sep 2026 07:23:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1788506586; x=1820042586; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=KZO6NKGFWh42W8EDKB6Cv9PvJ5QcQHaMowjGJpnytk4=; b=Kw6WeiY9EbBx0GTD7PFKytRSgzDvHm5h4fVQ7XJN5oOCs6BcIFzekVzr 2MKPClX4+QyKUCYfdd6DxaxEOWYGxgbIrPmys0MVcVbPR8lXHkAS1yeu4 oE/9NwcZwP/e87rgy/6hByjXj4HtBErz2YP6/vF5pPLIN5gi5RLxKu3gn xPA8Jz9e3FlqYCVVsI4J4d6uKMQd54dYrtL7GltJZrZqRO7oUY0fy4/WN oLEXPzHS+jUvr1zKI1MuT6f+R9fU5eGmyzZokpScoP/ULXzIuctW5pB5N LK01PigsGulUIt+gK6TMiVsM2xknd/tz120GfKnaXW+m8NZFGkCVktQFf Q==; X-CSE-ConnectionGUID: cwsuTM7JSqymhCSASklSMA== X-CSE-MsgGUID: O5Is+tIXTHy3oIzLQ+v1Eg== X-IronPort-AV: E=McAfee;i="6800,10657,11895"; a="92822948" X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="92822948" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Sep 2026 00:23:06 -0700 X-CSE-ConnectionGUID: vgQAMguJRAOk11Ul28W2RQ== X-CSE-MsgGUID: KrLzkRmhT12/vpeKL504Iw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="269424444" Received: from varungup-desk.iind.intel.com ([10.190.238.71]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Sep 2026 00:23:05 -0700 From: Arvind Yadav To: intel-xe@lists.freedesktop.org Cc: matthew.brost@intel.com, himal.prasad.ghimiray@intel.com, thomas.hellstrom@linux.intel.com, Sashiko Subject: [PATCH v2] drm/xe/vm: Handle purged BOs in VM snapshots Date: Fri, 4 Sep 2026 12:52:52 +0530 Message-ID: <20260904072252.4009491-1-arvind.yadav@intel.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" A purged BO can remain in a VM after its TTM resource has been freed. xe_vm_snapshot_capture() can then dereference a NULL resource while capturing a devcoredump. Record -ENODATA for the affected VMA instead of dereferencing the resource. v2: - Read the BO resource once with READ_ONCE(). (Matt) Fixes: ad9843aac91a ("drm/xe/madvise: Implement purgeable buffer object support") Reported-by: Sashiko Closes: https://sashiko.dev/#/patchset/20260831064942.315720-17-tejas.upadhyay%40intel.com?part=4 Cc: Thomas Hellström Cc: Himal Prasad Ghimiray Cc: Matthew Brost Signed-off-by: Arvind Yadav --- drivers/gpu/drm/xe/xe_vm.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index 19b3d0be7928..fcdd34c4f0fa 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -4663,20 +4663,29 @@ struct xe_vm_snapshot *xe_vm_snapshot_capture(struct xe_vm *vm) XE_VM_SNAP_FLAG_READ_ONLY : 0; snap->snap[i].pat_index = vma->attr.pat_index; if (bo) { + struct ttm_resource *res; + snap->snap[i].cpu_caching = bo->cpu_caching; snap->snap[i].bo = xe_bo_get(bo); snap->snap[i].bo_ofs = xe_vma_bo_offset(vma); - switch (bo->ttm.resource->mem_type) { - case XE_PL_SYSTEM: - case XE_PL_TT: - snap->snap[i].uapi_mem_region = 0; - break; - case XE_PL_VRAM0: - snap->snap[i].uapi_mem_region = 1; - break; - case XE_PL_VRAM1: - snap->snap[i].uapi_mem_region = 2; - break; + snap->snap[i].uapi_mem_region = -1; + + res = READ_ONCE(bo->ttm.resource); + if (!res) { + snap->snap[i].data = ERR_PTR(-ENODATA); + } else { + switch (res->mem_type) { + case XE_PL_SYSTEM: + case XE_PL_TT: + snap->snap[i].uapi_mem_region = 0; + break; + case XE_PL_VRAM0: + snap->snap[i].uapi_mem_region = 1; + break; + case XE_PL_VRAM1: + snap->snap[i].uapi_mem_region = 2; + break; + } } } else if (xe_vma_is_userptr(vma)) { struct mm_struct *mm = -- 2.43.0