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Commit f24659d9 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Linus Torvalds
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kprobes: support probing module __init function 



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: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Acked-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0deddf43

kernel/kprobes.c

+19 −4
Original line number Diff line number Diff line
@@ -677,6 +677,16 @@ int __kprobes register_kprobe(struct kprobe *p) 
			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();
@@ -1073,19 +1083,24 @@ static int __kprobes kprobes_module_callback(struct notifier_block *nb, 
	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,