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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E6F2C433EF for ; Tue, 7 Jun 2022 21:42:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378373AbiFGVmY (ORCPT ); Tue, 7 Jun 2022 17:42:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378552AbiFGUwP (ORCPT ); Tue, 7 Jun 2022 16:52:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F4231248F1; Tue, 7 Jun 2022 11:42:26 -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 dfw.source.kernel.org (Postfix) with ESMTPS id CBFA1615CE; Tue, 7 Jun 2022 18:42:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8B92C385A2; Tue, 7 Jun 2022 18:42:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654627345; bh=M/NcB8WX6Wqp97huGdzefR0XgbpT9OSioDVVk20zTLM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RCa9l8ut/cWRrsnqajJkEYS34MOkrnn9/jdsxUSGavt/d9en5Leoze0miDDv/xd3G qC/OSvQ3IYp223ekJaLEJ+lmv7beNN4PbKihBPCFqbjn1TqnN7XxmdxEn3oS1CNjJ4 bklndcumDA34WXP7yRPZeVcyY2YTEPuYJuwEUAbM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guo Ren , Guo Ren , Masami Hiramatsu Subject: [PATCH 5.17 707/772] csky: patch_text: Fixup last cpu should be master Date: Tue, 7 Jun 2022 19:04:59 +0200 Message-Id: <20220607165009.881028038@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164948.980838585@linuxfoundation.org> References: <20220607164948.980838585@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guo Ren commit 8c4d16471e2babe9bdfe41d6ef724526629696cb 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: 33e53ae1ce41 ("csky: Add kprobes supported") Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Masami Hiramatsu Cc: Signed-off-by: Greg Kroah-Hartman --- arch/csky/kernel/probes/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/csky/kernel/probes/kprobes.c +++ b/arch/csky/kernel/probes/kprobes.c @@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void struct csky_insn_patch *param = priv; unsigned int addr = (unsigned int)param->addr; - if (atomic_inc_return(¶m->cpu_count) == 1) { + if (atomic_inc_return(¶m->cpu_count) == num_online_cpus()) { *(u16 *) addr = cpu_to_le16(param->opcode); dcache_wb_range(addr, addr + 2); atomic_inc(¶m->cpu_count);