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 BC607F34C4B for ; Mon, 13 Apr 2026 12:26:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 32EE010E440; Mon, 13 Apr 2026 12:26:29 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="SB+LKMgH"; dkim-atps=neutral Received: from mail-dl1-f44.google.com (mail-dl1-f44.google.com [74.125.82.44]) by gabe.freedesktop.org (Postfix) with ESMTPS id A4C8F10E11B for ; Sun, 12 Apr 2026 04:39:49 +0000 (UTC) Received: by mail-dl1-f44.google.com with SMTP id a92af1059eb24-12c1a170a50so2998691c88.0 for ; Sat, 11 Apr 2026 21:39:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775968789; x=1776573589; darn=lists.freedesktop.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=kRdR1dc5/UfNuJsTk7iiKeGwmqYxW3GpWumyMvQ9lak=; b=SB+LKMgHXGkveG5Q1oEfx5JIj5q6ru45/+0WlJ66mtPjwbR7kUDyZ7R/+nnRnqVV1d ZhYtTjz4I3QjX4WCUE59KfcLKh+NRiH1oRw8QK1gONmsT4G8w4VIvIEzQDC4+kByLQkX YlX6zioCFWxifvuh9clQGNswBfnhTvFlY6SDMpKhUKvh4ifyYGGhTKWoQgI6W6VI77qY bnlOuFEq5SC2ACtmr6qCb3oFgdW2e6L7F37nUQhamZ34F7BHLCPu2WaNVQlV0kfPwG1F FmbRhHeQ8pOOXsBsnXTufjslh04mq+52USYkSGvsvJjyNY1+qaIbYHWoCo03hEGGmIt6 hTfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775968789; x=1776573589; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=kRdR1dc5/UfNuJsTk7iiKeGwmqYxW3GpWumyMvQ9lak=; b=F+EABr9wbW5RzsbZZQsAYmGsYsHROoYIw9JyALFFmI1hyj8m4Afdfcfja9V686hhD+ fMunAWlYOzQU0NHqwTQGzmcUMwDgGZkdBKgVA7budrH3OTCJn0GkEzo+MHCZuvhCQ/WG pW1anWLUrEvgUK4+SGN5vOeYfsobP7zJm6PNofP7ejA8jpm5gE3mGTtUlYXI7aExhIpB S7Icq1qRgGPPs/KnHOpYT8cVBZAxHO9p01Ka4zY7FPe6AjgvOrO+r2LwArToMfBpDJor kIp8yAvYiAsrh7Zz5KREDNSmH99LHoOo1KauNq0IW0SDmZTGCDbFLVeGAGsE0LwIm61B 5U/Q== X-Gm-Message-State: AOJu0YzWB97TdpxtVWMskEfqlGDmAVOkFVF/axD65+spoRWWAVqtvkHd fHt/3euQs5xpbBYubSt3COnOmbSVMDMdnD91VtJHutaIhKaL90ICJimu X-Gm-Gg: AeBDies5VclXt7FrJMoPj9UEUyYDPwiU/qZz1VnMOXns8M8mp0+gt+QmPbEZt+oqj1x unz0xaECVaizw0jkBML5BdC9DD7BEX5FiVeGpHF1T0NWtXcDOhP25c8MJmNE73JM2xd1M3h5geo csY8LKzILZxWh26BFCCFzeEEBFgrph1g6nNCvh9UCKpKy8NCbIgAYLMLjuEl8jdp1IK/et6t4Pi pL7osz+z6IYkYLgmhHH1VeC2GvDJzQD3+Qp6H4msz30ym7rNfQnRUovmPnwoeQIVPM1y/Cp+H2l RDtLgwhVZjN4KOq3IOFJnwaJrscmJSw9InbN0MpdFq1E2JU5/oG2N8NBA0Bi+lXdVjeV6UV9Tg8 jlTziz5tyLD9WEb8mu9gOh4CySGUXxr9ES+TyGa0jbGZCtjb0qiGy1uCAfS/R0e7hK9izi28UcG pKjcsPFWCjLtTHMSohW1ORiNB0+hIHy8jOv3cN X-Received: by 2002:a05:7022:517:b0:128:dab3:f528 with SMTP id a92af1059eb24-12c34e892c2mr5118834c88.8.1775968788704; Sat, 11 Apr 2026 21:39:48 -0700 (PDT) Received: from fedora ([2601:644:937c:6c90::f8b0]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2d561bde70csm13449412eec.15.2026.04.11.21.39.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Apr 2026 21:39:48 -0700 (PDT) Date: Sat, 11 Apr 2026 21:39:45 -0700 From: Vishal Moola To: Matthew Brost Cc: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, David Hildenbrand , Oscar Salvador , Andrew Morton , Balbir Singh , linux-mm@kvack.org, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/zone_device: Do not touch device folio after calling ->folio_free() Message-ID: References: <20260410230346.4009855-1-matthew.brost@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260410230346.4009855-1-matthew.brost@intel.com> X-Mailman-Approved-At: Mon, 13 Apr 2026 12:26:28 +0000 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" On Fri, Apr 10, 2026 at 04:03:46PM -0700, Matthew Brost wrote: > The contents of a device folio can immediately change after calling > ->folio_free(), as the folio may be reallocated by a driver with a > different order. Instead of touching the folio again to extract the > pgmap, use the local stack variable when calling percpu_ref_put_many(). > > Cc: David Hildenbrand > Cc: Oscar Salvador > Cc: Andrew Morton > Cc: Balbir Singh > Cc: linux-mm@kvack.org > Cc: linux-cxl@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Fixes: d245f9b4ab80 ("mm/zone_device: support large zone device private folios") > Signed-off-by: Matthew Brost With the cc-stable: Reviewed-by: Vishal Moola > --- > Stack trace: > > [ 631.875165] [IGT] xe_exec_system_allocator: starting subtest threads-many-new-prefetch > [ 632.282992] Oops: general protection fault, probably for non-canonical address 0x900000000000000: 0000 [#1] SMP NOPTI > [ 632.293469] CPU: 8 UID: 0 PID: 59267 Comm: xe_exec_system_ Not tainted 7.0.0-rc7-xe+ #281 PREEMPT(full) > [ 632.316023] RIP: 0010:free_zone_device_folio+0x149/0x240 > [ 632.339782] RSP: 0000:ffffc90023d1fd00 EFLAGS: 00010206 > [ 632.344947] RAX: 0900000000000000 RBX: 0000000000000001 RCX: 0000000094472d4d > [ 632.351991] RDX: ffffffff8155c76f RSI: 000000006f2213bf RDI: 000000008e84943a > [ 632.359042] RBP: ffffea0ff4030001 R08: 0000000000000000 R09: 0000000000000001 > [ 632.366094] R10: 0000000000000028 R11: 0000000000000000 R12: ffff88811828e400 > [ 632.373145] R13: 0000000000000000 R14: 000fffffc0000000 R15: 0000000000100073 > [ 632.380194] FS: 00007f2f0fdfe6c0(0000) GS:ffff88890a7e7000(0000) knlGS:0000000000000000 > [ 632.388186] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 632.393870] CR2: 00007f2f002e90f8 CR3: 0000000106708002 CR4: 0000000000f70ef0 > [ 632.400919] PKRU: 55555554 > [ 632.403605] Call Trace: > [ 632.406039] > [ 632.408131] do_swap_page+0x146d/0x18c0 > [ 632.411938] ? __pte_offset_map+0x3e/0x190 > [ 632.415994] __handle_mm_fault+0x6e8/0x8d0 > [ 632.420053] handle_mm_fault+0xbf/0x250 > [ 632.423855] ? lock_mm_and_find_vma+0x41/0x6f0 > [ 632.428256] do_user_addr_fault+0x168/0x690 > [ 632.432399] exc_page_fault+0x74/0x200 > [ 632.436117] asm_exc_page_fault+0x26/0x30 > [ 632.440092] RIP: 0033:0x5587554ff70d > [ 632.462142] RSP: 002b:00007f2f0fdfc970 EFLAGS: 00010246 > [ 632.467308] RAX: 0000000000003fc0 RBX: 00007f2f082e1fc0 RCX: 00007f2f12b3287d > [ 632.474355] RDX: 0000000000000000 RSI: 00000000c048644a RDI: 0000000000000003 > [ 632.481404] RBP: 00007f2f082e1fc0 R08: 00007f2f0fdfc958 R09: 0000000000000066 > [ 632.488450] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > [ 632.495495] R13: 00007f2f082de000 R14: 0000000000c00002 R15: 00007f2f1319e000 > [ 632.502547] > --- > mm/memremap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memremap.c b/mm/memremap.c > index ac7be07e3361..053842d45cb1 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -454,7 +454,7 @@ void free_zone_device_folio(struct folio *folio) > if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free)) > break; > pgmap->ops->folio_free(folio); > - percpu_ref_put_many(&folio->pgmap->ref, nr); > + percpu_ref_put_many(&pgmap->ref, nr); > break; > > case MEMORY_DEVICE_GENERIC: > -- > 2.34.1 >