linux-kernel - [PATCH 2/2] livepatch: __klp_disable_patch() should never be called for disabled patches

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Date:   Fri, 20 Oct 2017 16:56:51 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Jiri Kosina <jikos@...nel.org>,
        Joe Lawrence <joe.lawrence@...hat.com>
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>, Jessica Yu <jeyu@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Chris J Arges <chris.j.arges@...onical.com>,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Petr Mladek <pmladek@...e.com>
Subject: [PATCH 2/2] livepatch: __klp_disable_patch() should never be called for disabled patches

__klp_disable_patch() should never be called when the patch is not
enabled. Let's add the same warning that we have in __klp_enable_patch().

This allows to remove the check when calling klp_pre_unpatch_callback().
It was strange anyway because it repeatedly checked per-patch flag
for each patched object.

Signed-off-by: Petr Mladek <pmladek@...e.com>
---
 kernel/livepatch/core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index eb134479c394..287f71e9dbfe 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -282,6 +282,9 @@ static int __klp_disable_patch(struct klp_patch *patch)
 {
 	struct klp_object *obj;
 
+	if (WARN_ON(!patch->enabled))
+		return -EINVAL;
+
 	if (klp_transition_patch)
 		return -EBUSY;
 
@@ -293,7 +296,7 @@ static int __klp_disable_patch(struct klp_patch *patch)
 	klp_init_transition(patch, KLP_UNPATCHED);
 
 	klp_for_each_object(patch, obj)
-		if (patch->enabled && obj->patched)
+		if (obj->patched)
 			klp_pre_unpatch_callback(obj);
 
 	/*
-- 
1.8.5.6