Copilot commented on code in PR #12988:
URL: https://github.com/apache/trafficserver/pull/12988#discussion_r2954690426
##########
src/proxy/ReverseProxy.cc:
##########
@@ -68,22 +69,28 @@ int
init_reverse_proxy()
{
ink_assert(rewrite_table.load() == nullptr);
- reconfig_mutex = new_ProxyMutex();
- rewrite_table.store(new UrlRewrite());
+ reconfig_mutex = new_ProxyMutex();
+ auto *initial_table = new UrlRewrite();
- rewrite_table.load()->acquire();
+ initial_table->acquire();
Note("%s loading ...", ts::filename::REMAP);
- if (!rewrite_table.load()->load()) {
+ if (!initial_table->load()) {
Emergency("%s failed to load", ts::filename::REMAP);
} else {
Note("%s finished loading", ts::filename::REMAP);
}
+ rewrite_table.store(initial_table, std::memory_order_release);
+
RecRegisterConfigUpdateCb("proxy.config.url_remap.filename", url_rewrite_CB,
(void *)FILE_CHANGED);
RecRegisterConfigUpdateCb("proxy.config.proxy_name", url_rewrite_CB, (void
*)TSNAME_CHANGED);
RecRegisterConfigUpdateCb("proxy.config.reverse_proxy.enabled",
url_rewrite_CB, (void *)REVERSE_CHANGED);
RecRegisterConfigUpdateCb("proxy.config.http.referer_default_redirect",
url_rewrite_CB, (void *)HTTP_DEFAULT_REDIRECT_CHANGED);
+ if (initial_table->is_valid() && CacheProcessor::IsCacheEnabled() ==
CacheInitState::INITIALIZED) {
+ init_remap_volume_host_records();
+ }
+
Review Comment:
After `rewrite_table.store(initial_table, ...)`, the only reference that
keeps `initial_table` alive is the global lease; if a remap reload is
triggered, `reloadUrlRewrite()` will `exchange()` and `release()` the old
table, potentially deleting it on ET_TASK. The subsequent
`initial_table->is_valid()` dereference can become a use-after-free. To avoid
this, don’t dereference `initial_table` after publishing it unless you hold an
additional `acquire()`/`release()` pair, or re-load/acquire the table from
`rewrite_table` for the validity check; alternatively, perform the cache-ready
initialization before registering callbacks that can trigger reloads.
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