Add a function that allows external users (such as live patching
mechanisms) to check whether a given function (identified by symbol name)
has a kprobe installed in it.
Signed-off-by: Jiri Kosina <jkos...@suse.cz>
---
include/linux/kprobes.h | 5 +++++
kernel/kprobes.c | 28 ++++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index f7296e5..f760555 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -384,6 +384,7 @@ int disable_kprobe(struct kprobe *kp);
int enable_kprobe(struct kprobe *kp);
void dump_kprobe(struct kprobe *kp);
+bool kprobe_is_function_probed(const char *name);
#else /* !CONFIG_KPROBES: */
@@ -459,6 +460,10 @@ static inline int enable_kprobe(struct kprobe *kp)
{
return -ENOSYS;
}
+static inline bool kprobe_is_function_probed(const char *name)
+{
+ return false;
+}
#endif /* CONFIG_KPROBES */
static inline int disable_kretprobe(struct kretprobe *rp)
{
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3995f54..27e8ddb 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2036,6 +2036,34 @@ void dump_kprobe(struct kprobe *kp)
NOKPROBE_SYMBOL(dump_kprobe);
/*
+ * Check whether a given symbol is a probed function
+ */
+bool kprobe_is_function_probed(const char *name)
+{
+ struct hlist_head *head;
+ struct kprobe *p, *kp;
+ const char *sym = NULL;
+ unsigned long offset = 0;
+ unsigned int i;
+ char *modname, namebuf[KSYM_NAME_LEN];
+
+ preempt_disable();
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, head, hlist) {
+ sym = kallsyms_lookup((unsigned long)p->addr,
+ NULL, &offset, &modname,
+ namebuf);
+ if (!strcmp(sym, name))
+ return true;
+ }
+ }
+ preempt_enable();
+ return false;
+}
+EXPORT_SYMBOL_GPL(kprobe_is_function_probed);
+
+/*
* Lookup and populate the kprobe_blacklist.
*
* Unlike the kretprobe blacklist, we'll need to determine
--
1.9.2
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