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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-05-12 21:52:04 (GMT)
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-05-12 21:52:04 (GMT)
commit94a7a4e908f3020045d1ae64c7ee4e70b14f2a5e (patch)
treec3c0e49c6f3c42d2457d7649ca5632fdbde8bc6b /variable.c
parent98746acff3ee24d63b31549da5399df7ff32bc72 (diff)
autoload: always wait on loading thread
We cannot assume autoload_provided/rb_feature_provided returning TRUE means it is safe to proceed without waiting. Another thread may call rb_provide_feature before setting the constant (via autoload_const_set). So we must wait until autoload is completed by another thread. Note: this patch was tested with an explicit rb_thread_schedule in rb_provide_feature to make the race condition more apparent as suggested by <s.wanabe@gmail.com>: > --- a/load.c > +++ b/load.c > @@ -563,6 +563,7 @@ rb_provide_feature(VALUE feature) > rb_str_freeze(feature); > > rb_ary_push(features, rb_fstring(feature)); > +rb_thread_schedule(); > features_index_add(feature, INT2FIX(RARRAY_LEN(features)-1)); > reset_loaded_features_snapshot(); > } * variable.c (check_autoload_required): do not assume a provided feature means autoload is complete, always wait if autoload is being performed by another thread. [ruby-core:81105] [Bug #11384] Thanks to <s.wanabe@gmail.com> git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58696 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'variable.c')
-rw-r--r--variable.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/variable.c b/variable.c
index 6e883c7..63c5f2a 100644
--- a/variable.c
+++ b/variable.c
@@ -1987,6 +1987,17 @@ check_autoload_required(VALUE mod, ID id, const char **loadingpath)
if (!RSTRING_LEN(file) || !*RSTRING_PTR(file)) {
rb_raise(rb_eArgError, "empty file name");
}
+
+ /*
+ * if somebody else is autoloading, we MUST wait for them, since
+ * rb_provide_feature can provide a feature before autoload_const_set
+ * completes. We must wait until autoload_const_set finishes in
+ * the other thread.
+ */
+ if (ele->state && ele->state->thread != rb_thread_current()) {
+ return load;
+ }
+
loading = RSTRING_PTR(file);
safe = rb_safe_level();
rb_set_safe_level_force(0);