From nobody Thu Dec 18 00:45:39 2025 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 662B8CDB47E for ; Fri, 13 Oct 2023 12:00:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231751AbjJMMAA (ORCPT ); Fri, 13 Oct 2023 08:00:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231417AbjJML7n (ORCPT ); Fri, 13 Oct 2023 07:59:43 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A62F195; Fri, 13 Oct 2023 04:59:32 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44EB7C433CC; Fri, 13 Oct 2023 11:59:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697198371; bh=ZIdTdcHLWr/sOB8PSUXqF37fOevVbYeiYj5kEREzCsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R/IY2FxF4nhhUiT9TcBAKeVscINBGdP8AOURhdYyTW5OdOfQPSZhvxYgXNeF+OSLB RZVjG9nesoqKrx0CGwMsydjOREuwtc65EUqeu+/3QHAj+jZA9G5GbZ0NyYpbGFvUeG 9TcLiTxVjjklcl+q7u6hIfeDjRpwpmq7/Q0zVA1GKs9CgRLDGKM/p+cCh1GvrOxznk 6KYgWu3arpTEttQ3S5QGF6qK9c84lWZ6/RVHVR173t9EcGx9TF21volEDZ2+J/g7HQ z/xqXH25wBkZO6aeKcj11GQWPjrvDjTjhhH58xIC894Soi7glIXnRRIEhjMzsVUgYN hw6qmljXrTeOg== From: Frederic Weisbecker To: LKML Cc: "Paul E. McKenney" , Boqun Feng , Joel Fernandes , Josh Triplett , Mathieu Desnoyers , Neeraj Upadhyay , Steven Rostedt , Uladzislau Rezki , rcu , Frederic Weisbecker Subject: [PATCH 08/18] rcu: Eliminate rcu_gp_slow_unregister() false positive Date: Fri, 13 Oct 2023 13:58:52 +0200 Message-Id: <20231013115902.1059735-9-frederic@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231013115902.1059735-1-frederic@kernel.org> References: <20231013115902.1059735-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Paul E. McKenney" When using rcutorture as a module, there are a number of conditions that can abort the modprobe operation, for example, when attempting to run both RCU CPU stall warning tests and forward-progress tests. This can cause rcu_torture_cleanup() to be invoked on the unwind path out of rcu_rcu_torture_init(), which will mean that rcu_gp_slow_unregister() is invoked without a matching rcu_gp_slow_register(). This will cause a splat because rcu_gp_slow_unregister() is passed rcu_fwd_cb_nodelay, which does not match a NULL pointer. This commit therefore forgives a mismatch involving a NULL pointer, thus avoiding this false-positive splat. Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index aae515071ffd..a83ecab77917 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1260,7 +1260,7 @@ EXPORT_SYMBOL_GPL(rcu_gp_slow_register); /* Unregister a counter, with NULL for not caring which. */ void rcu_gp_slow_unregister(atomic_t *rgssp) { - WARN_ON_ONCE(rgssp && rgssp !=3D rcu_gp_slow_suppress); + WARN_ON_ONCE(rgssp && rgssp !=3D rcu_gp_slow_suppress && rcu_gp_slow_supp= ress !=3D NULL); =20 WRITE_ONCE(rcu_gp_slow_suppress, NULL); } --=20 2.34.1