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Message-ID: <20140227073328.20992.84854.stgit@ltc230.yrl.intra.hitachi.co.jp>
Date: Thu, 27 Feb 2014 16:33:28 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>
Cc: Fenghua Yu <fenghua.yu@...el.com>,
Seiji Aguchi <seiji.aguchi@....com>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
Sandeepa Prabhu <sandeepa.prabhu@...aro.org>,
Frederic Weisbecker <fweisbec@...il.com>, x86@...nel.org,
Steven Rostedt <rostedt@...dmis.org>, fche@...hat.com,
mingo@...hat.com, systemtap@...rceware.org,
"H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...e.de>
Subject: [PATCH -tip v7 05/26] [BUGFIX] kprobes/x86: Prohibit probing on
debug_stack_*
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 <masami.hiramatsu.pt@...achi.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Seiji Aguchi <seiji.aguchi@....com>
---
arch/x86/kernel/cpu/common.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8e28bf2..fd9caa4 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -8,6 +8,7 @@
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/init.h>
+#include <linux/kprobes.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/io.h>
@@ -1159,6 +1160,7 @@ int is_debug_stack(unsigned long addr)
(addr <= __get_cpu_var(debug_stack_addr) &&
addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ));
}
+NOKPROBE_SYMBOL(is_debug_stack);
DEFINE_PER_CPU(u32, debug_idt_ctr);
@@ -1167,6 +1169,7 @@ void debug_stack_set_zero(void)
this_cpu_inc(debug_idt_ctr);
load_current_idt();
}
+NOKPROBE_SYMBOL(debug_stack_set_zero);
void debug_stack_reset(void)
{
@@ -1175,6 +1178,7 @@ void debug_stack_reset(void)
if (this_cpu_dec_return(debug_idt_ctr) == 0)
load_current_idt();
}
+NOKPROBE_SYMBOL(debug_stack_reset);
#else /* CONFIG_X86_64 */
--
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