[PATCH -tip v9 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt

Masami Hiramatsu
2014-04-17T08:17:52Z

Prohibit probing on native_set_debugreg and native_load_idt.
Since the kprobes uses do_debug for single stepping,
functions called from do_debug before notify_die must not
be probed.
And also native_load_idt is called from paranoid_exit when
returning int3, this also must not be probed.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
arch/x86/kernel/paravirt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index e136869..548d25f 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -390,8 +390,10 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
.end_context_switch = paravirt_nop,
};

-/* At this point, native_get_debugreg has a real function entry */
+/* At this point, native_get/set_debugreg has real function entries */
NOKPROBE_SYMBOL(native_get_debugreg);
+NOKPROBE_SYMBOL(native_set_debugreg);
+NOKPROBE_SYMBOL(native_load_idt);

struct pv_apic_ops pv_apic_ops = {
#ifdef CONFIG_X86_LOCAL_APIC