[PATCH v5 3/3] livepatch: add transition notices

Joe Lawrence
2017-08-31T14:54:13Z

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>
---
kernel/livepatch/transition.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 53887f0bca10..3d44a3cf27be 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 transition, unpatching\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");

/*
@@ -489,6 +497,9 @@ void klp_init_transition(struct klp_patch *patch, int state)

WARN_ON_ONCE(klp_target_state != KLP_UNDEFINED);

+ pr_debug("'%s': initializing %s transition\n", patch->mod->name,
+ klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
klp_transition_patch = patch;

/*
@@ -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;
--
1.8.3.1