diff options
| -rw-r--r-- | init/main.c | 7 | ||||
| -rw-r--r-- | kernel/module.c | 5 |
2 files changed, 12 insertions, 0 deletions
diff --git a/init/main.c b/init/main.c index a404936d85d8..fd37315835b4 100644 --- a/init/main.c +++ b/init/main.c @@ -1034,6 +1034,13 @@ __setup("rodata=", set_debug_rodata); static void mark_readonly(void) { if (rodata_enabled) { + /* + * load_module() results in W+X mappings, which are cleaned up + * with call_rcu_sched(). Let's make sure that queued work is + * flushed so that we don't hit false positives looking for + * insecure pages which are W+X. + */ + rcu_barrier_sched(); mark_rodata_ro(); rodata_test(); } else diff --git a/kernel/module.c b/kernel/module.c index ce8066b88178..c9bea7f2b43e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3517,6 +3517,11 @@ static noinline int do_init_module(struct module *mod) * walking this with preempt disabled. In all the failure paths, we * call synchronize_sched(), but we don't want to slow down the success * path, so use actual RCU here. + * Note that module_alloc() on most architectures creates W+X page + * mappings which won't be cleaned up until do_free_init() runs. Any + * code such as mark_rodata_ro() which depends on those mappings to + * be cleaned up needs to sync with the queued work - ie + * rcu_barrier_sched() */ call_rcu_sched(&freeinit->rcu, do_free_init); mutex_unlock(&module_mutex); |