From patchwork Tue Apr 26 08:21:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 566581 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 25C9CC4332F for ; Tue, 26 Apr 2022 08:51:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238137AbiDZIyB (ORCPT ); Tue, 26 Apr 2022 04:54:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347684AbiDZIvv (ORCPT ); Tue, 26 Apr 2022 04:51:51 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 005FCD399F; Tue, 26 Apr 2022 01:40:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C2617B81CFA; Tue, 26 Apr 2022 08:40:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29CEBC385A0; Tue, 26 Apr 2022 08:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962445; bh=wa6DKY7ihCAiI4ORJ4Lemo2W/kJEgxqyoapglfQxiiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ajQpFr4QiCMxUyQLMdVrQtgkaYRX/UQZN2Oz2Yf2e/gC1rkxB4Vcmula6ZgGIponB yLf0EI83n0KI2cR6gBE+Bv+hAM9CNztAbkx/5YtxaqFeEUMDwSMfTSXizlRSUDVqWX lLKVVuf0JxE47VS+yF9WcNSz7PYrTsocxQUfv2Wk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guo Ren , Guo Ren , Max Filippov , Masami Hiramatsu Subject: [PATCH 5.15 099/124] xtensa: patch_text: Fixup last cpu should be master Date: Tue, 26 Apr 2022 10:21:40 +0200 Message-Id: <20220426081750.114127201@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081747.286685339@linuxfoundation.org> References: <20220426081747.286685339@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Guo Ren commit ee69d4be8fd064cd08270b4808d2dfece3614ee0 upstream. These patch_text implementations are using stop_machine_cpuslocked infrastructure with atomic cpu_count. The original idea: When the master CPU patch_text, the others should wait for it. But current implementation is using the first CPU as master, which couldn't guarantee the remaining CPUs are waiting. This patch changes the last CPU as the master to solve the potential risk. Fixes: 64711f9a47d4 ("xtensa: implement jump_label support") Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Max Filippov Reviewed-by: Masami Hiramatsu Cc: Message-Id: <20220407073323.743224-4-guoren@kernel.org> Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman --- arch/xtensa/kernel/jump_label.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/xtensa/kernel/jump_label.c +++ b/arch/xtensa/kernel/jump_label.c @@ -40,7 +40,7 @@ static int patch_text_stop_machine(void { struct patch *patch = data; - if (atomic_inc_return(&patch->cpu_count) == 1) { + if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { local_patch_text(patch->addr, patch->data, patch->sz); atomic_inc(&patch->cpu_count); } else {