On Wed, 21 Jan 2015, Li Bin wrote:
> for disable_patch:
> The patch is unallowed to be disabled if one patch after has
> dependencies with it and has been enabled.
>
> for enable_patch:
> The patch is unallowed to be enabled if one patch before has
> dependencies with it and has been disabled.
>
> Signed-off-by: Li Bin <huawei.libin@xxxxxxxxxx>
> ---
> kernel/livepatch/core.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 60 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 7861ed2..a12a31c 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -114,6 +114,21 @@ static bool klp_is_patch_registered(struct klp_patch *patch)
> return false;
> }
>
> +static bool klp_func_in_patch(struct klp_func *kfunc, struct klp_patch *patch)
> +{
> + struct klp_object *obj;
> + struct klp_func *func;
> +
> + for (obj = patch->objs; obj->funcs; obj++) {
> + for (func = obj->funcs; func->old_name; func++) {
> + if (kfunc->old_addr == func->old_addr) {
> + return true;
> + }
> + }
> + }
> + return false;
> +}
> +
> static bool klp_initialized(void)
> {
> return klp_root_kobj;
> @@ -466,8 +481,31 @@ unregister:
> static int __klp_disable_patch(struct klp_patch *patch)
> {
> struct klp_object *obj;
> + struct klp_patch *temp;
> + struct klp_func *func;
> int ret;
>
> + /*
> + * the patch is unallowed to be disabled if one patch
> + * after has dependencies with it and has been enabled.
> + */
> + for (temp = list_next_entry(patch, list);
> + &temp->list != &klp_patches;
> + temp = list_next_entry(temp, list)) {
> + if (temp->state != KLP_ENABLED)
> + continue;
> +
> + for (obj = patch->objs; obj->funcs; obj++) {
> + for (func = obj->funcs; func->old_name; func++) {
> + if (klp_func_in_patch(func, temp)) {
> + pr_err("this patch depends on '%s', please disable it firstly\n",
> + temp->mod->name);
> + return -EBUSY;
> + }
> + }
> + }
> + }
> +
> pr_notice("disabling patch '%s'\n", patch->mod->name);
>
> for (obj = patch->objs; obj->funcs; obj++) {
> @@ -519,11 +557,33 @@ EXPORT_SYMBOL_GPL(klp_disable_patch);
> static int __klp_enable_patch(struct klp_patch *patch)
> {
> struct klp_object *obj;
> + struct klp_patch *temp;
> + struct klp_func *func;
> int ret;
>
> if (WARN_ON(patch->state != KLP_DISABLED))
> return -EINVAL;
>
> + /*
> + * the patch is unallowed to be enabled if one patch
> + * before has dependencies with it and has been disabled.
> + */
> + for (temp = list_first_entry(&klp_patches, struct klp_patch, list);
> + temp != patch; temp = list_next_entry(temp, list)) {
> + if (temp->state != KLP_DISABLED)
> + continue;
> +
> + for (obj = patch->objs; obj->funcs; obj++) {
> + for (func = obj->funcs; func->old_name; func++) {
> + if (klp_func_in_patch(func, temp)) {
> + pr_err("this patch depends on '%s', please enable it firstly\n",
> + temp->mod->name);
> + return -EBUSY;
By this you limit the definition of the patch inter-dependency to just
symbols. But that's not the only way how patches can depend on it other --
the dependency can be semantical.
--
Jiri Kosina
SUSE Labs
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