kprobes: return proper error code from register_kprobe() (f986a499) · Commits · 戴 / test

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:

Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by:

Prashanth K Nageshappa <prashanth@linux.vnet.ibm.com> Acked-by:

Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jason Baron <jbaron@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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 @@ out:

		return ret;

		fail_with_jump_label:
		cannot_probe:
		preempt_enable();
		jump_label_unlock();
		return ret;

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