summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--arch/i386/kernel/kprobes.c4
-rw-r--r--arch/ia64/kernel/kprobes.c2
-rw-r--r--arch/powerpc/kernel/kprobes.c2
-rw-r--r--arch/s390/kernel/kprobes.c2
-rw-r--r--arch/x86_64/kernel/kprobes.c2
-rw-r--r--include/linux/kprobes.h2
-rw-r--r--kernel/kprobes.c117
7 files changed, 103 insertions, 28 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index fc79e1e..af1d533 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -184,7 +184,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
+ free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
mutex_unlock(&kprobe_mutex);
}
@@ -333,7 +333,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
return 1;
ss_probe:
-#ifndef CONFIG_PREEMPT
+#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
if (p->ainsn.boostable == 1 && !p->post_handler){
/* Boost up -- we can execute copied instructions directly */
reset_current_kprobe();
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 51217d6..4d592ee 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -481,7 +481,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
+ free_insn_slot(p->ainsn.insn, 0);
mutex_unlock(&kprobe_mutex);
}
/*
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 7b8d12b..4657563 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -85,7 +85,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
+ free_insn_slot(p->ainsn.insn, 0);
mutex_unlock(&kprobe_mutex);
}
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 67914fe..576368c 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -200,7 +200,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
+ free_insn_slot(p->ainsn.insn, 0);
mutex_unlock(&kprobe_mutex);
}
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index ac24156..209c8c0 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -224,7 +224,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
+ free_insn_slot(p->ainsn.insn, 0);
mutex_unlock(&kprobe_mutex);
}
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index ac4c055..769be39 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -165,7 +165,7 @@ extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
extern kprobe_opcode_t *get_insn_slot(void);
-extern void free_insn_slot(kprobe_opcode_t *slot);
+extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
/* Get the kprobe at this addr (if any) - called with preemption disabled */
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 610c837..17ec4af 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -38,6 +38,7 @@
#include <linux/module.h>
#include <linux/moduleloader.h>
#include <linux/kallsyms.h>
+#include <linux/freezer.h>
#include <asm-generic/sections.h>
#include <asm/cacheflush.h>
#include <asm/errno.h>
@@ -83,9 +84,36 @@ struct kprobe_insn_page {
kprobe_opcode_t *insns; /* Page of instruction slots */
char slot_used[INSNS_PER_PAGE];
int nused;
+ int ngarbage;
};
static struct hlist_head kprobe_insn_pages;
+static int kprobe_garbage_slots;
+static int collect_garbage_slots(void);
+
+static int __kprobes check_safety(void)
+{
+ int ret = 0;
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
+ ret = freeze_processes();
+ if (ret == 0) {
+ struct task_struct *p, *q;
+ do_each_thread(p, q) {
+ if (p != current && p->state == TASK_RUNNING &&
+ p->pid != 0) {
+ printk("Check failed: %s is running\n",p->comm);
+ ret = -1;
+ goto loop_end;
+ }
+ } while_each_thread(p, q);
+ }
+loop_end:
+ thaw_processes();
+#else
+ synchronize_sched();
+#endif
+ return ret;
+}
/**
* get_insn_slot() - Find a slot on an executable page for an instruction.
@@ -96,6 +124,7 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
struct kprobe_insn_page *kip;
struct hlist_node *pos;
+ retry:
hlist_for_each(pos, &kprobe_insn_pages) {
kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
if (kip->nused < INSNS_PER_PAGE) {
@@ -112,7 +141,11 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
}
}
- /* All out of space. Need to allocate a new page. Use slot 0.*/
+ /* If there are any garbage slots, collect it and try again. */
+ if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
+ goto retry;
+ }
+ /* All out of space. Need to allocate a new page. Use slot 0. */
kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
if (!kip) {
return NULL;
@@ -133,10 +166,62 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
memset(kip->slot_used, 0, INSNS_PER_PAGE);
kip->slot_used[0] = 1;
kip->nused = 1;
+ kip->ngarbage = 0;
return kip->insns;
}
-void __kprobes free_insn_slot(kprobe_opcode_t *slot)
+/* Return 1 if all garbages are collected, otherwise 0. */
+static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
+{
+ kip->slot_used[idx] = 0;
+ kip->nused--;
+ if (kip->nused == 0) {
+ /*
+ * Page is no longer in use. Free it unless
+ * it's the last one. We keep the last one
+ * so as not to have to set it up again the
+ * next time somebody inserts a probe.
+ */
+ hlist_del(&kip->hlist);
+ if (hlist_empty(&kprobe_insn_pages)) {
+ INIT_HLIST_NODE(&kip->hlist);
+ hlist_add_head(&kip->hlist,
+ &kprobe_insn_pages);
+ } else {
+ module_free(NULL, kip->insns);
+ kfree(kip);
+ }
+ return 1;
+ }
+ return 0;
+}
+
+static int __kprobes collect_garbage_slots(void)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos, *next;
+
+ /* Ensure no-one is preepmted on the garbages */
+ if (check_safety() != 0)
+ return -EAGAIN;
+
+ hlist_for_each_safe(pos, next, &kprobe_insn_pages) {
+ int i;
+ kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
+ if (kip->ngarbage == 0)
+ continue;
+ kip->ngarbage = 0; /* we will collect all garbages */
+ for (i = 0; i < INSNS_PER_PAGE; i++) {
+ if (kip->slot_used[i] == -1 &&
+ collect_one_slot(kip, i))
+ break;
+ }
+ }
+ kprobe_garbage_slots = 0;
+ return 0;
+}
+
+void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
{
struct kprobe_insn_page *kip;
struct hlist_node *pos;
@@ -146,28 +231,18 @@ void __kprobes free_insn_slot(kprobe_opcode_t *slot)
if (kip->insns <= slot &&
slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
int i = (slot - kip->insns) / MAX_INSN_SIZE;
- kip->slot_used[i] = 0;
- kip->nused--;
- if (kip->nused == 0) {
- /*
- * Page is no longer in use. Free it unless
- * it's the last one. We keep the last one
- * so as not to have to set it up again the
- * next time somebody inserts a probe.
- */
- hlist_del(&kip->hlist);
- if (hlist_empty(&kprobe_insn_pages)) {
- INIT_HLIST_NODE(&kip->hlist);
- hlist_add_head(&kip->hlist,
- &kprobe_insn_pages);
- } else {
- module_free(NULL, kip->insns);
- kfree(kip);
- }
+ if (dirty) {
+ kip->slot_used[i] = -1;
+ kip->ngarbage++;
+ } else {
+ collect_one_slot(kip, i);
}
- return;
+ break;
}
}
+ if (dirty && (++kprobe_garbage_slots > INSNS_PER_PAGE)) {
+ collect_garbage_slots();
+ }
}
#endif
OpenPOWER on IntegriCloud