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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1327CC4724C for ; Fri, 1 May 2020 13:42:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB9F3208DB for ; Fri, 1 May 2020 13:42:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588340530; bh=6T0RzNca53fTcr0xsQ0bozFXTxhOw2weySWR/MkjV7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ro8KfcXcd2oDTJjdRwlEA7jBGXx57F4ih6ifLFCEqV3yFlMcOZMopdlQp4Fztpq1F lfjH+Hg48XjFDOtyWEbqXDzKWE8Ou/XXYuFv8hkUEjCxybdS78mPpYyGkHyw92AEpT Ta5KO6bTdPz0W2lOHw1tIVBvWeijbz8AKfC5yzmE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731476AbgEANmK (ORCPT ); Fri, 1 May 2020 09:42:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:42470 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729712AbgEANmC (ORCPT ); Fri, 1 May 2020 09:42:02 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 11C80205C9; Fri, 1 May 2020 13:42:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588340521; bh=6T0RzNca53fTcr0xsQ0bozFXTxhOw2weySWR/MkjV7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZFYeKgawYwZqU0mrazowHzDiL8PcxDoraQkwZPnlcdedvn4Br3E0ErzdRu1rdevZP k4hTHCNtZnsCwtsnAGG7fzUGkiN3BYMACtxQN/VMivkIxvFMIKogDjruK3/ceA04QS KZVP5BI/8QqGnbkAl1mrR5NcKK2u0mSaMNdHyDxM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Philipp Rudo , Vasily Gorbik Subject: [PATCH 5.6 016/106] s390/ftrace: fix potential crashes when switching tracers Date: Fri, 1 May 2020 15:22:49 +0200 Message-Id: <20200501131546.168126327@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200501131543.421333643@linuxfoundation.org> References: <20200501131543.421333643@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Philipp Rudo commit 8ebf6da9db1b2a20bb86cc1bee2552e894d03308 upstream. Switching tracers include instruction patching. To prevent that a instruction is patched while it's read the instruction patching is done in stop_machine 'context'. This also means that any function called during stop_machine must not be traced. Thus add 'notrace' to all functions called within stop_machine. Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls") Fixes: 38f2c691a4b3 ("s390: improve wait logic of stop_machine") Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield") Signed-off-by: Philipp Rudo Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/diag.c | 2 +- arch/s390/kernel/smp.c | 4 ++-- arch/s390/kernel/trace.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) --- a/arch/s390/kernel/diag.c +++ b/arch/s390/kernel/diag.c @@ -133,7 +133,7 @@ void diag_stat_inc(enum diag_stat_enum n } EXPORT_SYMBOL(diag_stat_inc); -void diag_stat_inc_norecursion(enum diag_stat_enum nr) +void notrace diag_stat_inc_norecursion(enum diag_stat_enum nr) { this_cpu_inc(diag_stat.counter[nr]); trace_s390_diagnose_norecursion(diag_map[nr].code); --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -403,7 +403,7 @@ int smp_find_processor_id(u16 address) return -1; } -bool arch_vcpu_is_preempted(int cpu) +bool notrace arch_vcpu_is_preempted(int cpu) { if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) return false; @@ -413,7 +413,7 @@ bool arch_vcpu_is_preempted(int cpu) } EXPORT_SYMBOL(arch_vcpu_is_preempted); -void smp_yield_cpu(int cpu) +void notrace smp_yield_cpu(int cpu) { if (!MACHINE_HAS_DIAG9C) return; --- a/arch/s390/kernel/trace.c +++ b/arch/s390/kernel/trace.c @@ -14,7 +14,7 @@ EXPORT_TRACEPOINT_SYMBOL(s390_diagnose); static DEFINE_PER_CPU(unsigned int, diagnose_trace_depth); -void trace_s390_diagnose_norecursion(int diag_nr) +void notrace trace_s390_diagnose_norecursion(int diag_nr) { unsigned long flags; unsigned int *depth;