On Tue, 6 Feb 2018, Petr Mladek wrote: > From: Jason Baron <jbaron@xxxxxxxxxx> > > We are going to add a feature called atomic replace. It will allow to > create a patch that would replace all already registered patches. > > The replaced patches will stay registered because they are typically > unregistered by some package uninstall scripts. But we will remove > these patches from @klp_patches list to keep the enabled patch > on the bottom of the stack. Otherwise, we would need to implement > rather complex logic for moving the patches on the stack. Also > it would complicate implementation of the atomic replace feature. > It is not worth it. > > As a result, we will have patches that are registered but that > are not longer usable. Let's get prepared for this and use > a better descriptive name for klp_is_patch_registered() function. > > Also create separate list for the replaced patches and allow to > unregister them. Alternative solution would be to add a flag > into struct klp_patch. Note that patch->kobj.state_initialized > is not safe because it can be cleared outside klp_mutex. > > This patch does not change the existing behavior. > > Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx> > [pmladek@xxxxxxxx: Split and renamed klp_is_patch_usable()] > Signed-off-by: Petr Mladek <pmladek@xxxxxxxx> > Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > Cc: Jessica Yu <jeyu@xxxxxxxxxx> > Cc: Jiri Kosina <jikos@xxxxxxxxxx> > Cc: Miroslav Benes <mbenes@xxxxxxx> > --- > kernel/livepatch/core.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c > index fccb603942f1..11632fe8716a 100644 > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -47,6 +47,13 @@ DEFINE_MUTEX(klp_mutex); > > static LIST_HEAD(klp_patches); > > +/* > + * List of 'replaced' patches that have been replaced by a patch that has the > + * 'replace' bit set. When they are added to this list, they are disabled and > + * can not be re-enabled, but they can be unregistered(). > + */ > +LIST_HEAD(klp_replaced_patches); It should be static, I think. It is used only in kernel/livepatch/core.c. And sparse complains about it. With that fixed Acked-by: Miroslav Benes <mbenes@xxxxxxx> Miroslav -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
