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authorJiri Kosina <jkosina@suse.cz>2018-01-31 18:33:52 +0300
committerJiri Kosina <jkosina@suse.cz>2018-01-31 18:36:38 +0300
commitd05b695c25bf0d704c74e0e1375de893531b9424 (patch)
tree793ac54576aa7f8316579aa0123a3879273193cd /kernel/livepatch
parent8869016d3a58cbe7c31c70f4f008a92122b271c7 (diff)
parentd0807da78e11d46f18399cbf8c4028c731346766 (diff)
downloadlinux-d05b695c25bf0d704c74e0e1375de893531b9424.tar.xz
Merge branch 'for-4.16/remove-immediate' into for-linus
Pull 'immediate' feature removal from Miroslav Benes.
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/core.c12
-rw-r--r--kernel/livepatch/transition.c49
2 files changed, 6 insertions, 55 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 8fd8e8f126da..3a4656fb7047 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -366,11 +366,6 @@ static int __klp_enable_patch(struct klp_patch *patch)
/*
* A reference is taken on the patch module to prevent it from being
* unloaded.
- *
- * Note: For immediate (no consistency model) patches we don't allow
- * patch modules to unload since there is no safe/sane method to
- * determine if a thread is still running in the patched code contained
- * in the patch module once the ftrace registration is successful.
*/
if (!try_module_get(patch->mod))
return -ENODEV;
@@ -894,12 +889,7 @@ int klp_register_patch(struct klp_patch *patch)
if (!klp_initialized())
return -ENODEV;
- /*
- * Architectures without reliable stack traces have to set
- * patch->immediate because there's currently no way to patch kthreads
- * with the consistency model.
- */
- if (!klp_have_reliable_stack() && !patch->immediate) {
+ if (!klp_have_reliable_stack()) {
pr_err("This architecture doesn't have support for the livepatch consistency model.\n");
return -ENOSYS;
}
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index be5bfa533ee8..7c6631e693bc 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -82,7 +82,6 @@ static void klp_complete_transition(void)
struct klp_func *func;
struct task_struct *g, *task;
unsigned int cpu;
- bool immediate_func = false;
pr_debug("'%s': completing %s transition\n",
klp_transition_patch->mod->name,
@@ -104,16 +103,9 @@ static void klp_complete_transition(void)
klp_synchronize_transition();
}
- if (klp_transition_patch->immediate)
- goto done;
-
- klp_for_each_object(klp_transition_patch, obj) {
- klp_for_each_func(obj, func) {
+ klp_for_each_object(klp_transition_patch, obj)
+ klp_for_each_func(obj, func)
func->transition = false;
- if (func->immediate)
- immediate_func = true;
- }
- }
/* Prevent klp_ftrace_handler() from seeing KLP_UNDEFINED state */
if (klp_target_state == KLP_PATCHED)
@@ -132,7 +124,6 @@ static void klp_complete_transition(void)
task->patch_state = KLP_UNDEFINED;
}
-done:
klp_for_each_object(klp_transition_patch, obj) {
if (!klp_is_object_loaded(obj))
continue;
@@ -146,16 +137,11 @@ done:
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
/*
- * See complementary comment in __klp_enable_patch() for why we
- * keep the module reference for immediate patches.
- *
- * klp_forced or immediate_func set implies unbounded increase of
- * module's ref count if the module is disabled/enabled in a loop.
+ * klp_forced set implies unbounded increase of module's ref count if
+ * the module is disabled/enabled in a loop.
*/
- if (!klp_forced && !klp_transition_patch->immediate &&
- !immediate_func && klp_target_state == KLP_UNPATCHED) {
+ if (!klp_forced && klp_target_state == KLP_UNPATCHED)
module_put(klp_transition_patch->mod);
- }
klp_target_state = KLP_UNDEFINED;
klp_transition_patch = NULL;
@@ -223,9 +209,6 @@ static int klp_check_stack_func(struct klp_func *func,
struct klp_ops *ops;
int i;
- if (func->immediate)
- return 0;
-
for (i = 0; i < trace->nr_entries; i++) {
address = trace->entries[i];
@@ -388,13 +371,6 @@ void klp_try_complete_transition(void)
WARN_ON_ONCE(klp_target_state == KLP_UNDEFINED);
/*
- * If the patch can be applied or reverted immediately, skip the
- * per-task transitions.
- */
- if (klp_transition_patch->immediate)
- goto success;
-
- /*
* Try to switch the tasks to the target patch state by walking their
* stacks and looking for any to-be-patched or to-be-unpatched
* functions. If such functions are found on a stack, or if the stack
@@ -437,7 +413,6 @@ void klp_try_complete_transition(void)
return;
}
-success:
/* we're done, now cleanup the data structures */
klp_complete_transition();
}
@@ -458,13 +433,6 @@ void klp_start_transition(void)
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
/*
- * If the patch can be applied or reverted immediately, skip the
- * per-task transitions.
- */
- if (klp_transition_patch->immediate)
- return;
-
- /*
* Mark all normal tasks as needing a patch state update. They'll
* switch either in klp_try_complete_transition() or as they exit the
* kernel.
@@ -514,13 +482,6 @@ void klp_init_transition(struct klp_patch *patch, int state)
klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
/*
- * If the patch can be applied or reverted immediately, skip the
- * per-task transitions.
- */
- if (patch->immediate)
- return;
-
- /*
* Initialize all tasks to the initial patch state to prepare them for
* switching to the target state.
*/