(2012/02/15 15:48), Prashanth Nageshappa wrote:
> 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 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.
Looks good to me! :)
>
> Signed-off-by: Ananth N Mavinakayanahalli <[email protected]>
> Signed-off-by: Prashanth K Nageshappa <[email protected]>
> Cc: [email protected]
Acked-by: Masami Hiramatsu <[email protected]>
Thank you,
> ---
>
> kernel/kprobes.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> Index: linux-14feb/kernel/kprobes.c
> ===================================================================
> --- linux-14feb.orig/kernel/kprobes.c
> +++ linux-14feb/kernel/kprobes.c
> @@ -1334,8 +1334,10 @@ int __kprobes register_kprobe(struct kpr
> 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 kpr
> * 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 kpr
> 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 kpr
>
> return ret;
>
> -fail_with_jump_label:
> +cannot_probe:
> preempt_enable();
> jump_label_unlock();
> return ret;
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: [email protected]
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