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Commit f986a499 authored by Prashanth Nageshappa's avatar Prashanth Nageshappa Committed by Linus Torvalds
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kprobes: return proper error code from register_kprobe() 



register_kprobe() aborts if the address of the new request falls in a
prohibited area (such as ftrace pouch, __kprobes annotated functions,
non-kernel text addresses, jump label text).  We however don't return the
right error on this abort, resulting in a silent failure - incorrect
adding/reporting of kprobes ('perf probe do_fork+18' or 'perf probe
mcount' for instance).

In V2 we are incorporating Masami Hiramatsu's  feedback.

This patch fixes it by returning -EINVAL upon failure.

While we are here, rename the label used for exit to be more appropriate.

Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarPrashanth K Nageshappa <prashanth@linux.vnet.ibm.com>
Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c22ab332

kernel/kprobes.c

+7 −5
Original line number Diff line number Diff line
@@ -1334,8 +1334,10 @@ int __kprobes register_kprobe(struct kprobe *p) 
	if (!kernel_text_address((unsigned long) p->addr) ||

	    in_kprobes_functions((unsigned long) p->addr) ||

	    ftrace_text_reserved(p->addr, p->addr) ||

	    jump_label_text_reserved(p->addr, p->addr))

		goto fail_with_jump_label;

	    jump_label_text_reserved(p->addr, p->addr)) {

		ret = -EINVAL;

		goto cannot_probe;

	}



	/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */

	p->flags &= KPROBE_FLAG_DISABLED;
@@ -1352,7 +1354,7 @@ int __kprobes register_kprobe(struct kprobe *p) 
		 * its code to prohibit unexpected unloading.

		 */

		if (unlikely(!try_module_get(probed_mod)))

			goto fail_with_jump_label;

			goto cannot_probe;



		/*

		 * If the module freed .init.text, we couldn't insert
@@ -1361,7 +1363,7 @@ int __kprobes register_kprobe(struct kprobe *p) 
		if (within_module_init((unsigned long)p->addr, probed_mod) &&

		    probed_mod->state != MODULE_STATE_COMING) {

			module_put(probed_mod);

			goto fail_with_jump_label;

			goto cannot_probe;

		}

		/* ret will be updated by following code */

	}
@@ -1409,7 +1411,7 @@ int __kprobes register_kprobe(struct kprobe *p) 


	return ret;



fail_with_jump_label:

cannot_probe:

	preempt_enable();

	jump_label_unlock();

	return ret;