rec: comment on an issue encountered runnig asan on trixie

diff --git a/meson/sanitizers/meson.build b/meson/sanitizers/meson.build
index d708ba79fe14af231a06ff053d1558b5ec3ab2dc..afeb398c5a9ee85c9d9f9f8e0e88683efdb20173 100644 (file)
--- a/meson/sanitizers/meson.build
+++ b/meson/sanitizers/meson.build
@@ -2,6 +2,11 @@ opt_sanitize = get_option('b_sanitize')
 
 if opt_sanitize == 'address' or opt_sanitize == 'address,undefined'
   subdir('address-sanitizer-fiber-switching')
+  conf.set(
+    'HAVE_LEAK_SANITIZER_INTERFACE',
+    cxx.has_header('sanitizer/lsan_interface.h'),
+    description: 'Have leak sanitizer inteface',
+  )
 endif
 
 if opt_sanitize != 'none'

diff --git a/pdns/recursordist/mtasker_context.cc b/pdns/recursordist/mtasker_context.cc
index 1bd3fd8ae12ac574f7b5cf7dce1017f5916c2915..06766b16ba05006c41f79cbe1b2058488bb5e8c0 100644 (file)
--- a/pdns/recursordist/mtasker_context.cc
+++ b/pdns/recursordist/mtasker_context.cc
@@ -118,6 +118,10 @@ extern "C"
   threadWrapper(intptr_t const xargs)
   {
 #else
+  // If you see asan trouble in this function, run with
+  // ASAN_OPTIONS=detect_stack_use_after_return=0 or completely disable it by comping with
+  // -fsanitize-address-use-after-return=never.  On debian clang versions up and including 14 do
+  // not seem to trigger a problem here, but starting from version 15 they do.
   threadWrapper(transfer_t const theThread)
   {
 #endif