[compiler-rt] [hwasan] Report unavalible fixed shadow range (PR #98574)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Vitaly Buka (vitalybuka)

<details>
<summary>Changes</summary>

Before the patch fixed-shadow.c died with obscure SEGV mapping shadow over libc.so.


---
Full diff: https://github.com/llvm/llvm-project/pull/98574.diff


2 Files Affected:

- (modified) compiler-rt/lib/hwasan/hwasan_linux.cpp (+9) 
- (modified) compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c (+12-9) 


``````````diff
diff --git a/compiler-rt/lib/hwasan/hwasan_linux.cpp b/compiler-rt/lib/hwasan/hwasan_linux.cpp
index 0a23ffc9fa1ba..68294b5962569 100644
--- a/compiler-rt/lib/hwasan/hwasan_linux.cpp
+++ b/compiler-rt/lib/hwasan/hwasan_linux.cpp
@@ -109,6 +109,15 @@ static void InitializeShadowBaseAddress(uptr shadow_size_bytes) {
   // FIXME: Android should init flags before shadow.
   if (!SANITIZER_ANDROID && flags()->fixed_shadow_base != (uptr)-1) {
     __hwasan_shadow_memory_dynamic_address = flags()->fixed_shadow_base;
+    uptr beg = __hwasan_shadow_memory_dynamic_address;
+    uptr end = beg + shadow_size_bytes;
+    if (!MemoryRangeIsAvailable(beg, end)) {
+      Report(
+          "FATAL: HWAddressSanitizer: Shadow range %p-%p is not available.\n",
+          (void *)beg, (void *)end);
+      DumpProcessMap();
+      CHECK(MemoryRangeIsAvailable(beg, end));
+    }
   } else {
     __hwasan_shadow_memory_dynamic_address =
         FindDynamicShadowStart(shadow_size_bytes);
diff --git a/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c b/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c
index ab6ff52027926..e450c100959d1 100644
--- a/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c
+++ b/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c
@@ -1,15 +1,19 @@
 // Test fixed shadow base functionality.
 //
 // Default compiler instrumentation works with any shadow base (dynamic or fixed).
-// RUN: %clang_hwasan %s -o %t && %run %t
-// RUN: %clang_hwasan %s -o %t && HWASAN_OPTIONS=fixed_shadow_base=263878495698944 %run %t
-// RUN: %clang_hwasan %s -o %t && HWASAN_OPTIONS=fixed_shadow_base=4398046511104 %run %t
+// RUN: %clang_hwasan %s -o %t
+// RUN: %run %t
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=263878495698944 %run %t 2>%t.out || (cat %t.out | FileCheck %s)
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=4398046511104 %run %t 2>%t.out || (cat %t.out | FileCheck %s)
 //
 // If -hwasan-mapping-offset is set, then the fixed_shadow_base needs to match.
-// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=263878495698944 -o %t && HWASAN_OPTIONS=fixed_shadow_base=263878495698944 %run %t
-// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=4398046511104 -o %t && HWASAN_OPTIONS=fixed_shadow_base=4398046511104 %run %t
-// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=263878495698944 -o %t && HWASAN_OPTIONS=fixed_shadow_base=4398046511104 not %run %t
-// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=4398046511104 -o %t && HWASAN_OPTIONS=fixed_shadow_base=263878495698944 not %run %t
+// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=263878495698944 -o %t
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=263878495698944 %run %t 2>%t.out || (cat %t.out | FileCheck %s)
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=4398046511104 not %run %t
+
+// RUN: %clang_hwasan %s -mllvm -hwasan-mapping-offset=4398046511104 -o %t
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=4398046511104 %run %t 2>%t.out || (cat %t.out | FileCheck %s)
+// RUN: HWASAN_OPTIONS=fixed_shadow_base=263878495698944 not %run %t
 //
 // Note: if fixed_shadow_base is not set, compiler-rt will dynamically choose a
 // shadow base, which has a tiny but non-zero probability of matching the
@@ -22,8 +26,7 @@
 //
 // UNSUPPORTED: android
 
-// FIXME: SEGV on Ubuntu 24.04. Looking.
-// UNSUPPORTED: linux
+// CHECK: FATAL: HWAddressSanitizer: Shadow range {{.*}} is not available
 
 #include <assert.h>
 #include <sanitizer/allocator_interface.h>

``````````

</details>


https://github.com/llvm/llvm-project/pull/98574