[PATCH 2/3] static_call: Fix static_call_text_reserved() vs __init

Peter Zijlstra
2021-06-28T11:34:36Z

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>
---
kernel/static_call.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -292,13 +292,15 @@ static int addr_conflict(struct static_c

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_reserv

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

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;