Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753930Ab3J3Kxq (ORCPT ); Wed, 30 Oct 2013 06:53:46 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:39488 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691Ab3J3Kxo (ORCPT ); Wed, 30 Oct 2013 06:53:44 -0400 X-AuditID: 85900ec0-d272ab9000001514-8b-5270e5369943 Subject: [PATCH -tip 1/2] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* To: Ingo Molnar From: Masami Hiramatsu Cc: Fenghua Yu , Seiji Aguchi , Ananth N Mavinakayanahalli , x86@kernel.org, lkml , "Steven Rostedt (Red Hat)" , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Borislav Petkov Date: Wed, 30 Oct 2013 10:53:41 +0000 Message-ID: <20131030105341.7997.48258.stgit@kbuild-fedora.novalocal> In-Reply-To: <20131030105334.7997.750.stgit@kbuild-fedora.novalocal> References: <20131030105334.7997.750.stgit@kbuild-fedora.novalocal> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2007 Lines: 62 Prohibit probing on debug_stack_reset and debug_stack_set_zero. Since the both functions are called from TRACE_IRQS_ON/OFF_DEBUG macros which run in int3 ist entry, probing it may cause a soft lockup. This happens when the kernel built with CONFIG_DYNAMIC_FTRACE=y and CONFIG_TRACE_IRQFLAGS=y. Signed-off-by: Masami Hiramatsu Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Borislav Petkov Cc: Fenghua Yu Cc: Seiji Aguchi --- arch/x86/kernel/cpu/common.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 35e28b0..8712a1a 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -1158,7 +1159,7 @@ DEFINE_PER_CPU(struct orig_ist, orig_ist); static DEFINE_PER_CPU(unsigned long, debug_stack_addr); DEFINE_PER_CPU(int, debug_stack_usage); -int is_debug_stack(unsigned long addr) +int __kprobes is_debug_stack(unsigned long addr) { return __get_cpu_var(debug_stack_usage) || (addr <= __get_cpu_var(debug_stack_addr) && @@ -1167,13 +1168,13 @@ int is_debug_stack(unsigned long addr) DEFINE_PER_CPU(u32, debug_idt_ctr); -void debug_stack_set_zero(void) +void __kprobes debug_stack_set_zero(void) { this_cpu_inc(debug_idt_ctr); load_current_idt(); } -void debug_stack_reset(void) +void __kprobes debug_stack_reset(void) { if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/