Prohibit probing on the functions called before kprobe_int3_handler() in do_int3(). More specifically, ftrace_int3_handler(), poke_int3_handler(), and ist_enter(). And since rcu_nmi_enter() is called by ist_enter(), it also should be marked as NOKPROBE_SYMBOL.
Since those are handled before kprobe_int3_handler(), probing those functions can cause a breakpoint recursion and crash the kernel.
Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- arch/x86/kernel/alternative.c | 3 ++- arch/x86/kernel/ftrace.c | 3 ++- arch/x86/kernel/traps.c | 1 + kernel/rcu/tree.c | 2 ++ 4 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index ebeac487a20c..e8b628b1b279 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -11,6 +11,7 @@ #include <linux/stop_machine.h> #include <linux/slab.h> #include <linux/kdebug.h> +#include <linux/kprobes.h> #include <asm/text-patching.h> #include <asm/alternative.h> #include <asm/sections.h> @@ -764,8 +765,8 @@ int poke_int3_handler(struct pt_regs *regs) regs->ip = (unsigned long) bp_int3_handler;
return 1; - } +NOKPROBE_SYMBOL(poke_int3_handler);
/** * text_poke_bp() -- update instructions on live kernel on SMP diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 7ee8067cbf45..22a548919228 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -269,7 +269,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return ret; }
-static int is_ftrace_caller(unsigned long ip) +static nokprobe_inline int is_ftrace_caller(unsigned long ip) { if (ip == ftrace_update_func) return 1; @@ -299,6 +299,7 @@ int ftrace_int3_handler(struct pt_regs *regs)
return 1; } +NOKPROBE_SYMBOL(ftrace_int3_handler);
static int ftrace_write(unsigned long ip, const char *val, int size) { diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 9b7c4ca8f0a7..e289ce1332ab 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -111,6 +111,7 @@ void ist_enter(struct pt_regs *regs) /* This code is a bit fragile. Test it. */ RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work"); } +NOKPROBE_SYMBOL(ist_enter);
void ist_exit(struct pt_regs *regs) { diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 9180158756d2..74db52a0a466 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -62,6 +62,7 @@ #include <linux/suspend.h> #include <linux/ftrace.h> #include <linux/tick.h> +#include <linux/kprobes.h>
#include "tree.h" #include "rcu.h" @@ -872,6 +873,7 @@ void rcu_nmi_enter(void) { rcu_nmi_enter_common(false); } +NOKPROBE_SYMBOL(rcu_nmi_enter);
/** * rcu_irq_enter - inform RCU that current CPU is entering irq away from idle