kprobes: Allow probe on some kprobe functions

There is no need to prohibit probing on the functions
used for preparation, registeration, optimization,
controll etc. Those are safely probed because those are
not invoked from breakpoint/fault/debug handlers,
there is no chance to cause recursive exceptions.

Following functions are now removed from the kprobes blacklist:

	add_new_kprobe
	aggr_kprobe_disabled
	alloc_aggr_kprobe
	alloc_aggr_kprobe
	arm_all_kprobes
	__arm_kprobe
	arm_kprobe
	arm_kprobe_ftrace
	check_kprobe_address_safe
	collect_garbage_slots
	collect_garbage_slots
	collect_one_slot
	debugfs_kprobe_init
	__disable_kprobe
	disable_kprobe
	disarm_all_kprobes
	__disarm_kprobe
	disarm_kprobe
	disarm_kprobe_ftrace
	do_free_cleaned_kprobes
	do_optimize_kprobes
	do_unoptimize_kprobes
	enable_kprobe
	force_unoptimize_kprobe
	free_aggr_kprobe
	free_aggr_kprobe
	__free_insn_slot
	__get_insn_slot
	get_optimized_kprobe
	__get_valid_kprobe
	init_aggr_kprobe
	init_aggr_kprobe
	in_nokprobe_functions
	kick_kprobe_optimizer
	kill_kprobe
	kill_optimized_kprobe
	kprobe_addr
	kprobe_optimizer
	kprobe_queued
	kprobe_seq_next
	kprobe_seq_start
	kprobe_seq_stop
	kprobes_module_callback
	kprobes_open
	optimize_all_kprobes
	optimize_kprobe
	prepare_kprobe
	prepare_optimized_kprobe
	register_aggr_kprobe
	register_jprobe
	register_jprobes
	register_kprobe
	register_kprobes
	register_kretprobe
	register_kretprobe
	register_kretprobes
	register_kretprobes
	report_probe
	show_kprobe_addr
	try_to_optimize_kprobe
	unoptimize_all_kprobes
	unoptimize_kprobe
	unregister_jprobe
	unregister_jprobes
	unregister_kprobe
	__unregister_kprobe_bottom
	unregister_kprobes
	__unregister_kprobe_top
	unregister_kretprobe
	unregister_kretprobe
	unregister_kretprobes
	unregister_kretprobes
	wait_for_kprobe_optimizer

I tested those functions by putting kprobes on all
instructions in the functions with the bash script
I sent to LKML. See:

  https://lkml.org/lkml/2014/3/27/33

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20140417081753.26341.57889.stgit@ltc230.yrl.intra.hitachi.co.jp
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: fche@redhat.com
Cc: systemtap@sourceware.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 76 insertions, 77 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 5ffc6875d2a7..4db2cc616f50 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -138,13 +138,13 @@ struct kprobe_insn_cache kprobe_insn_slots = {
         .insn_size = MAX_INSN_SIZE,
         .nr_garbage = 0,
 };
-static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
+static int collect_garbage_slots(struct kprobe_insn_cache *c);
 
 /**
  * __get_insn_slot() - Find a slot on an executable page for an instruction.
  * We allocate an executable page if there's no room on existing ones.
  */
-kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
+kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
 {
         struct kprobe_insn_page *kip;
         kprobe_opcode_t *slot = NULL;
@@ -201,7 +201,7 @@ out:
 }
 
 /* Return 1 if all garbages are collected, otherwise 0. */
-static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
+static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
 {
         kip->slot_used[idx] = SLOT_CLEAN;
         kip->nused--;
@@ -222,7 +222,7 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
         return 0;
 }
 
-static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
+static int collect_garbage_slots(struct kprobe_insn_cache *c)
 {
         struct kprobe_insn_page *kip, *next;
 
@@ -244,8 +244,8 @@ static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
         return 0;
 }
 
-void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
-                                kprobe_opcode_t *slot, int dirty)
+void __free_insn_slot(struct kprobe_insn_cache *c,
+                      kprobe_opcode_t *slot, int dirty)
 {
         struct kprobe_insn_page *kip;
 
@@ -361,7 +361,7 @@ void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
 }
 
 /* Free optimized instructions and optimized_kprobe */
-static __kprobes void free_aggr_kprobe(struct kprobe *p)
+static void free_aggr_kprobe(struct kprobe *p)
 {
         struct optimized_kprobe *op;
 
@@ -399,7 +399,7 @@ static inline int kprobe_disarmed(struct kprobe *p)
 }
 
 /* Return true(!0) if the probe is queued on (un)optimizing lists */
-static int __kprobes kprobe_queued(struct kprobe *p)
+static int kprobe_queued(struct kprobe *p)
 {
         struct optimized_kprobe *op;
 
@@ -415,7 +415,7 @@ static int __kprobes kprobe_queued(struct kprobe *p)
  * Return an optimized kprobe whose optimizing code replaces
  * instructions including addr (exclude breakpoint).
  */
-static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
+static struct kprobe *get_optimized_kprobe(unsigned long addr)
 {
         int i;
         struct kprobe *p = NULL;
@@ -447,7 +447,7 @@ static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
  * Optimize (replace a breakpoint with a jump) kprobes listed on
  * optimizing_list.
  */
-static __kprobes void do_optimize_kprobes(void)
+static void do_optimize_kprobes(void)
 {
         /* Optimization never be done when disarmed */
         if (kprobes_all_disarmed || !kprobes_allow_optimization ||
@@ -475,7 +475,7 @@ static __kprobes void do_optimize_kprobes(void)
  * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
  * if need) kprobes listed on unoptimizing_list.
  */
-static __kprobes void do_unoptimize_kprobes(void)
+static void do_unoptimize_kprobes(void)
 {
         struct optimized_kprobe *op, *tmp;
 
@@ -507,7 +507,7 @@ static __kprobes void do_unoptimize_kprobes(void)
 }
 
 /* Reclaim all kprobes on the free_list */
-static __kprobes void do_free_cleaned_kprobes(void)
+static void do_free_cleaned_kprobes(void)
 {
         struct optimized_kprobe *op, *tmp;
 
@@ -519,13 +519,13 @@ static __kprobes void do_free_cleaned_kprobes(void)
 }
 
 /* Start optimizer after OPTIMIZE_DELAY passed */
-static __kprobes void kick_kprobe_optimizer(void)
+static void kick_kprobe_optimizer(void)
 {
         schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
 }
 
 /* Kprobe jump optimizer */
-static __kprobes void kprobe_optimizer(struct work_struct *work)
+static void kprobe_optimizer(struct work_struct *work)
 {
         mutex_lock(&kprobe_mutex);
         /* Lock modules while optimizing kprobes */
@@ -561,7 +561,7 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
 }
 
 /* Wait for completing optimization and unoptimization */
-static __kprobes void wait_for_kprobe_optimizer(void)
+static void wait_for_kprobe_optimizer(void)
 {
         mutex_lock(&kprobe_mutex);
 
@@ -580,7 +580,7 @@ static __kprobes void wait_for_kprobe_optimizer(void)
 }
 
 /* Optimize kprobe if p is ready to be optimized */
-static __kprobes void optimize_kprobe(struct kprobe *p)
+static void optimize_kprobe(struct kprobe *p)
 {
         struct optimized_kprobe *op;
 
@@ -614,7 +614,7 @@ static __kprobes void optimize_kprobe(struct kprobe *p)
 }
 
 /* Short cut to direct unoptimizing */
-static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
+static void force_unoptimize_kprobe(struct optimized_kprobe *op)
 {
         get_online_cpus();
         arch_unoptimize_kprobe(op);
@@ -624,7 +624,7 @@ static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
 }
 
 /* Unoptimize a kprobe if p is optimized */
-static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
+static void unoptimize_kprobe(struct kprobe *p, bool force)
 {
         struct optimized_kprobe *op;
 
@@ -684,7 +684,7 @@ static void reuse_unused_kprobe(struct kprobe *ap)
 }
 
 /* Remove optimized instructions */
-static void __kprobes kill_optimized_kprobe(struct kprobe *p)
+static void kill_optimized_kprobe(struct kprobe *p)
 {