libsanitizer: merge from master (c86b4503a94c277534ce4b9a5c015a6ac151b98a).

2 files changed, 36 insertions, 7 deletions

diff --git a/libsanitizer/hwasan/hwasan.cpp b/libsanitizer/hwasan/hwasan.cpp
index e8ffbbd6f48..c2863400d9d 100644
--- a/libsanitizer/hwasan/hwasan.cpp
+++ b/libsanitizer/hwasan/hwasan.cpp
@@ -16,6 +16,7 @@
 #include "hwasan_checks.h"
 #include "hwasan_dynamic_shadow.h"
 #include "hwasan_globals.h"
+#include "hwasan_mapping.h"
 #include "hwasan_poisoning.h"
 #include "hwasan_report.h"
 #include "hwasan_thread.h"
@@ -391,8 +392,15 @@ void __hwasan_print_shadow(const void *p, uptr sz) {
   uptr shadow_last = MemToShadow(ptr_raw + sz - 1);
   Printf("HWASan shadow map for %zx .. %zx (pointer tag %x)\n", ptr_raw,
          ptr_raw + sz, GetTagFromPointer((uptr)p));
-  for (uptr s = shadow_first; s <= shadow_last; ++s)
-    Printf("  %zx: %x\n", ShadowToMem(s), *(tag_t *)s);
+  for (uptr s = shadow_first; s <= shadow_last; ++s) {
+    tag_t mem_tag = *reinterpret_cast<tag_t *>(s);
+    uptr granule_addr = ShadowToMem(s);
+    if (mem_tag && mem_tag < kShadowAlignment)
+      Printf("  %zx: %02x(%02x)\n", granule_addr, mem_tag,
+             *reinterpret_cast<tag_t *>(granule_addr + kShadowAlignment - 1));
+    else
+      Printf("  %zx: %02x\n", granule_addr, mem_tag);
+  }
 }
 
 sptr __hwasan_test_shadow(const void *p, uptr sz) {
diff --git a/libsanitizer/hwasan/hwasan_report.cpp b/libsanitizer/hwasan/hwasan_report.cpp
index 9b3b661b74b..0107b8b772a 100644
--- a/libsanitizer/hwasan/hwasan_report.cpp
+++ b/libsanitizer/hwasan/hwasan_report.cpp
@@ -702,12 +702,33 @@ void ReportTagMismatch(StackTrace *stack, uptr tagged_addr, uptr access_size,
   tag_t mem_tag = *tag_ptr;
 
   Printf("%s", d.Access());
-  Printf("%s of size %zu at %p tags: %02x/%02x (ptr/mem) in thread T%zd\n",
-         is_store ? "WRITE" : "READ", access_size, untagged_addr, ptr_tag,
-         mem_tag, t->unique_id());
+  if (mem_tag && mem_tag < kShadowAlignment) {
+    tag_t *granule_ptr = reinterpret_cast<tag_t *>((untagged_addr + offset) &
+                                                   ~(kShadowAlignment - 1));
+    // If offset is 0, (untagged_addr + offset) is not aligned to granules.
+    // This is the offset of the leftmost accessed byte within the bad granule.
+    u8 in_granule_offset = (untagged_addr + offset) & (kShadowAlignment - 1);
+    tag_t short_tag = granule_ptr[kShadowAlignment - 1];
+    // The first mismatch was a short granule that matched the ptr_tag.
+    if (short_tag == ptr_tag) {
+      // If the access starts after the end of the short granule, then the first
+      // bad byte is the first byte of the access; otherwise it is the first
+      // byte past the end of the short granule
+      if (mem_tag > in_granule_offset) {
+        offset += mem_tag - in_granule_offset;
+      }
+    }
+    Printf(
+        "%s of size %zu at %p tags: %02x/%02x(%02x) (ptr/mem) in thread T%zd\n",
+        is_store ? "WRITE" : "READ", access_size, untagged_addr, ptr_tag,
+        mem_tag, short_tag, t->unique_id());
+  } else {
+    Printf("%s of size %zu at %p tags: %02x/%02x (ptr/mem) in thread T%zd\n",
+           is_store ? "WRITE" : "READ", access_size, untagged_addr, ptr_tag,
+           mem_tag, t->unique_id());
+  }
   if (offset != 0)
-    Printf("Invalid access starting at offset [%zu, %zu)\n", offset,
-           Min(access_size, static_cast<uptr>(offset) + (1 << kShadowScale)));
+    Printf("Invalid access starting at offset %zu\n", offset);
   Printf("%s", d.Default());
 
   stack->Print();