[asan] add an experimental flag protect_shadow_gap. If set to false, the shadow gap will not be mprotect-ed and all hell may break loose. But this makes CUDA's cuInit() pass.

llvm-svn: 253108

2 files changed, 3 insertions, 0 deletions

diff --git a/compiler-rt/lib/asan/asan_flags.inc b/compiler-rt/lib/asan/asan_flags.inc
index 406c494ddc7..c0ae0270512 100644
--- a/compiler-rt/lib/asan/asan_flags.inc
+++ b/compiler-rt/lib/asan/asan_flags.inc
@@ -75,6 +75,7 @@ ASAN_FLAG(bool, check_malloc_usable_size, true,
           "295.*.")
 ASAN_FLAG(bool, unmap_shadow_on_exit, false,
           "If set, explicitly unmaps the (huge) shadow at exit.")
+ASAN_FLAG(bool, protect_shadow_gap, true, "If set, mprotect the shadow gap")
 ASAN_FLAG(bool, print_stats, false,
           "Print various statistics after printing an error message or if "
           "atexit=1.")
diff --git a/compiler-rt/lib/asan/asan_rtl.cc b/compiler-rt/lib/asan/asan_rtl.cc
index 65e04972e44..c22add53d75 100644
--- a/compiler-rt/lib/asan/asan_rtl.cc
+++ b/compiler-rt/lib/asan/asan_rtl.cc
@@ -326,6 +326,8 @@ static void InitializeHighMemEnd() {
 }
 
 static void ProtectGap(uptr addr, uptr size) {
+  if (!flags()->protect_shadow_gap)
+    return;
   void *res = MmapNoAccess(addr, size, "shadow gap");
   if (addr == (uptr)res)
     return;