static_call: Fix static_call_text_reserved() vs __init

It turns out that static_call_text_reserved() was reporting __init
text as being reserved past the time when the __init text was freed
and re-used.

This is mostly harmless and will at worst result in refusing a kprobe.

Fixes: 6333e8f73b83 ("static_call: Avoid kprobes on inline static_call()s")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20210628113045.106211657@infradead.org

diff --git a/kernel/static_call.c b/kernel/static_call.c
index 723fcc9d20db69fbde09354cd988a2cbfef2847b..43ba0b1e0edbb935782675284e0d1cd28846f12b 100644 (file)
--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -292,13 +292,15 @@ static int addr_conflict(struct static_call_site *site, void *start, void *end)
 
 static int __static_call_text_reserved(struct static_call_site *iter_start,
                                       struct static_call_site *iter_stop,
-                                      void *start, void *end)
+                                      void *start, void *end, bool init)
 {
        struct static_call_site *iter = iter_start;
 
        while (iter < iter_stop) {
-               if (addr_conflict(iter, start, end))
-                       return 1;
+               if (init || !static_call_is_init(iter)) {
+                       if (addr_conflict(iter, start, end))
+                               return 1;
+               }
                iter++;
        }
 
@@ -324,7 +326,7 @@ static int __static_call_mod_text_reserved(void *start, void *end)
 
        ret = __static_call_text_reserved(mod->static_call_sites,
                        mod->static_call_sites + mod->num_static_call_sites,
-                       start, end);
+                       start, end, mod->state == MODULE_STATE_COMING);
 
        module_put(mod);
 
@@ -459,8 +461,9 @@ static inline int __static_call_mod_text_reserved(void *start, void *end)
 
 int static_call_text_reserved(void *start, void *end)
 {
+       bool init = system_state < SYSTEM_RUNNING;
        int ret = __static_call_text_reserved(__start_static_call_sites,
-                       __stop_static_call_sites, start, end);
+                       __stop_static_call_sites, start, end, init);
 
        if (ret)
                return ret;