From nobody Sun Feb 8 19:13:16 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A315C77B7E for ; Sat, 27 May 2023 11:04:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232165AbjE0LEl (ORCPT ); Sat, 27 May 2023 07:04:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231466AbjE0LEi (ORCPT ); Sat, 27 May 2023 07:04:38 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32882D3 for ; Sat, 27 May 2023 04:04:36 -0700 (PDT) Received: from fsav117.sakura.ne.jp (fsav117.sakura.ne.jp [27.133.134.244]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 34RB4HO3022407; Sat, 27 May 2023 20:04:17 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav117.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp); Sat, 27 May 2023 20:04:17 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 34RB4DsP022399 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Sat, 27 May 2023 20:04:17 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <5fa8dfeb-8eb6-0de0-a335-e0b4336c29e0@I-love.SAKURA.ne.jp> Date: Sat, 27 May 2023 20:04:11 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.1 Content-Language: en-US To: Eric Dumazet , Dmitry Vyukov , Jakub Kicinski , "David S. Miller" Cc: LKML From: Tetsuo Handa Subject: [PATCH] ref_tracker: add stack_depot_save() failure handling to ref_tracker_alloc() Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" stack_depot_save() cannot accept __GFP_NOFAIL flag because __stack_depot_save() drops gfp flags which are not in GFP_KERNEL | GFP_ATOMIC | __GFP_NOWARN. Also, changing __stack_depot_save() to accept __GFP_NOFAIL is not possible because rmqueue() does not want __GFP_NOFAIL flag for order =3D=3D DEPOT_POOL_ORDER allocation request. Therefore, assume that stack_depot_save(GFP_KERNEL | __GFP_NOFAIL) from ref_tracker_alloc() can silently fail, and emit "unreliable refcount tracker." message. Signed-off-by: Tetsuo Handa --- lib/ref_tracker.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index dc7b14aa3431..ad48ff19adb2 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -84,12 +84,18 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir, gfp_mask |=3D __GFP_NOFAIL; *trackerp =3D tracker =3D kzalloc(sizeof(*tracker), gfp_mask); if (unlikely(!tracker)) { +nomem: pr_err_once("memory allocation failure, unreliable refcount tracker.\n"); refcount_inc(&dir->untracked); return -ENOMEM; } nr_entries =3D stack_trace_save(entries, ARRAY_SIZE(entries), 1); tracker->alloc_stack_handle =3D stack_depot_save(entries, nr_entries, gfp= ); + if (!tracker->alloc_stack_handle) { + *trackerp =3D NULL; + kfree(tracker); + goto nomem; + } =20 spin_lock_irqsave(&dir->lock, flags); list_add(&tracker->head, &dir->list); --=20 2.18.4