[PATCH] D48806: [asan] Fix deadlock issue on FreeBSD, caused by use of .preinit_array in rL325240

[Fangrui Song via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL336067: [asan] Fix deadlock issue on FreeBSD, caused by use of .preinit_array in… (authored by MaskRay, committed by ).

Repository:
  rL LLVM

https://reviews.llvm.org/D48806

Files:
  compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
  compiler-rt/trunk/lib/xray/xray_init.cc


Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_internal_defs.h
@@ -98,11 +98,16 @@
 
 // We can use .preinit_array section on Linux to call sanitizer initialization
 // functions very early in the process startup (unless PIC macro is defined).
+//
+// On FreeBSD, .preinit_array functions are called with rtld_bind_lock writer
+// lock held. It will lead to dead lock if unresolved PLT functions (which helds
+// rtld_bind_lock reader lock) are called inside .preinit_array functions.
+//
 // FIXME: do we have anything like this on Mac?
 #ifndef SANITIZER_CAN_USE_PREINIT_ARRAY
-#if ((SANITIZER_LINUX && !SANITIZER_ANDROID) || \
-  SANITIZER_FREEBSD || SANITIZER_OPENBSD) && !defined(PIC)
-# define SANITIZER_CAN_USE_PREINIT_ARRAY 1
+#if ((SANITIZER_LINUX && !SANITIZER_ANDROID) || SANITIZER_OPENBSD) && \
+    !defined(PIC)
+#define SANITIZER_CAN_USE_PREINIT_ARRAY 1
 // Before Solaris 11.4, .preinit_array is fully supported only with GNU ld.
 // FIXME: Check for those conditions.
 #elif SANITIZER_SOLARIS && !defined(PIC)
Index: compiler-rt/trunk/lib/xray/xray_init.cc
===================================================================
--- compiler-rt/trunk/lib/xray/xray_init.cc
+++ compiler-rt/trunk/lib/xray/xray_init.cc
@@ -84,7 +84,13 @@
 #endif
 }
 
-#if !defined(XRAY_NO_PREINIT) && SANITIZER_CAN_USE_PREINIT_ARRAY
+// FIXME: Make check-xray tests work on FreeBSD without
+// SANITIZER_CAN_USE_PREINIT_ARRAY.
+// See sanitizer_internal_defs.h where the macro is defined.
+// Calling unresolved PLT functions in .preinit_array can lead to deadlock on
+// FreeBSD but here it seems benign.
+#if !defined(XRAY_NO_PREINIT) &&                                               \
+    (SANITIZER_CAN_USE_PREINIT_ARRAY || SANITIZER_FREEBSD)
 // Only add the preinit array initialization if the sanitizers can.
 __attribute__((section(".preinit_array"),
                used)) void (*__local_xray_preinit)(void) = __xray_init;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D48806.153652.patch
Type: text/x-patch
Size: 2143 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20180701/fb593edb/attachment.bin>