Allow kprobes to probe module __init routines.
When __init functions are freed, kprobes which probe those functions
are set to "Gone" flag. These "Gone" probes are disarmed from the code
and never be enabled.

Signed-off-by: Masami Hiramatsu
---
kernel/kprobes.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)

Index: 2.6.28-rc4/kernel/kprobes.c
================================================== =================
--- 2.6.28-rc4.orig/kernel/kprobes.c
+++ 2.6.28-rc4/kernel/kprobes.c
@@ -676,6 +676,16 @@ int __kprobes register_kprobe(struct kpr
preempt_enable();
return -EINVAL;
}
+ /*
+ * If the module freed .init.text, we couldn't insert
+ * kprobes in there.
+ */
+ if (within_module_init((unsigned long)p->addr, probed_mod) &&
+ probed_mod->state != MODULE_STATE_COMING) {
+ module_put(probed_mod);
+ preempt_enable();
+ return -EINVAL;
+ }
}
preempt_enable();

@@ -1072,19 +1082,24 @@ static int __kprobes kprobes_module_call
struct hlist_node *node;
struct kprobe *p;
unsigned int i;
+ int checkcore = (val == MODULE_STATE_GOING);

- if (val != MODULE_STATE_GOING)
+ if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE;

/*
- * module .text section will be freed. We need to
- * disable kprobes which have been inserted in the section.
+ * When MODULE_STATE_GOING was notified, both of module .text and
+ * .init.text sections would be freed. When MODULE_STATE_LIVE was
+ * notified, only .init.text section would be freed. We need to
+ * disable kprobes which have been inserted in the sections.
*/
mutex_lock(&kprobe_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
- if (within_module_core((unsigned long)p->addr, mod)) {
+ if (within_module_init((unsigned long)p->addr, mod) ||
+ (checkcore &&
+ within_module_core((unsigned long)p->addr, mod))) {
/*
* The vaddr this probe is installed will soon
* be vfreed buy not synced to disk. Hence,

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

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