livepatch: add transition notices

Log a few kernel debug messages at the beginning of the following livepatch
transition functions:

  klp_complete_transition()
  klp_cancel_transition()
  klp_init_transition()
  klp_reverse_transition()

Also update the log notice message in klp_start_transition() for similar
verbiage as the above messages.

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 17 insertions, 1 deletions

diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 53887f0bca10..56add6327736 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -82,6 +82,10 @@ static void klp_complete_transition(void)
         unsigned int cpu;
         bool immediate_func = false;
 
+        pr_debug("'%s': completing %s transition\n",
+                 klp_transition_patch->mod->name,
+                 klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
         if (klp_target_state == KLP_UNPATCHED) {
                 /*
                  * All tasks have transitioned to KLP_UNPATCHED so we can now
@@ -163,6 +167,9 @@ void klp_cancel_transition(void)
         if (WARN_ON_ONCE(klp_target_state != KLP_PATCHED))
                 return;
 
+        pr_debug("'%s': canceling patching transition, going to unpatch\n",
+                 klp_transition_patch->mod->name);
+
         klp_target_state = KLP_UNPATCHED;
         klp_complete_transition();
 }
@@ -441,7 +448,8 @@ void klp_start_transition(void)
 
         WARN_ON_ONCE(klp_target_state == KLP_UNDEFINED);
 
-        pr_notice("'%s': %s...\n", klp_transition_patch->mod->name,
+        pr_notice("'%s': starting %s transition\n",
+                  klp_transition_patch->mod->name,
                   klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
 
         /*
@@ -497,6 +505,9 @@ void klp_init_transition(struct klp_patch *patch, int state)
          */
         klp_target_state = state;
 
+        pr_debug("'%s': initializing %s transition\n", patch->mod->name,
+                 klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
         /*
          * If the patch can be applied or reverted immediately, skip the
          * per-task transitions.
@@ -562,6 +573,11 @@ void klp_reverse_transition(void)
         unsigned int cpu;
         struct task_struct *g, *task;
 
+        pr_debug("'%s': reversing transition from %s\n",
+                 klp_transition_patch->mod->name,
+                 klp_target_state == KLP_PATCHED ? "patching to unpatching" :
+                                                   "unpatching to patching");
+
         klp_transition_patch->enabled = !klp_transition_patch->enabled;
 
         klp_target_state = !klp_target_state;