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livepatch: Cancel transition a safe way for immediate patches 

klp_init_transition() does not set func->transition for immediate patches.
Then klp_ftrace_handler() could use the new code immediately. As a result,
it is not safe to put the livepatch module in klp_cancel_transition().

This patch reverts most of the last minute changes klp_cancel_transition().
It keeps the warning about a misuse because it still makes sense.

Fixes: 3ec24776bf ("livepatch: allow removal of a disabled patch")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Petr Mladek 2017-04-11 13:07:48 +02:00 committed by Jiri Kosina
parent 10517429b5
commit e679af627f
1 changed files with 0 additions and 20 deletions
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20
kernel/livepatch/transition.c
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@ -120,31 +120,11 @@ static void klp_complete_transition(void)
*/
void klp_cancel_transition(void)
{
struct klp_patch *patch = klp_transition_patch;
struct klp_object *obj;
struct klp_func *func;
bool immediate_func = false;
if (WARN_ON_ONCE(klp_target_state != KLP_PATCHED))
return;
klp_target_state = KLP_UNPATCHED;
klp_complete_transition();
/*
* In the enable error path, even immediate patches can be safely
* removed because the transition hasn't been started yet.
*
* klp_complete_transition() doesn't have a module_put() for immediate
* patches, so do it here.
*/
klp_for_each_object(patch, obj)
klp_for_each_func(obj, func)
if (func->immediate)
immediate_func = true;
if (patch->immediate || immediate_func)
module_put(patch->mod);
}
/*