[compiler-rt] e9c9fde - [scudo] Avoid accessing inaccessible pages in unmap() in secondary (#102367)

[via llvm-commits]

Author: ChiaHungDuan
Date: 2024-08-07T15:42:11-07:00
New Revision: e9c9fde3b766fd2c3904523a9be5e982ce56a825

URL: https://github.com/llvm/llvm-project/commit/e9c9fde3b766fd2c3904523a9be5e982ce56a825
DIFF: https://github.com/llvm/llvm-project/commit/e9c9fde3b766fd2c3904523a9be5e982ce56a825.diff

LOG: [scudo] Avoid accessing inaccessible pages in unmap() in secondary (#102367)

Added: 
    

Modified: 
    compiler-rt/lib/scudo/standalone/secondary.h

Removed: 
    


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diff  --git a/compiler-rt/lib/scudo/standalone/secondary.h b/compiler-rt/lib/scudo/standalone/secondary.h
index a9a7c2c8ea8618..51721fab52cedf 100644
--- a/compiler-rt/lib/scudo/standalone/secondary.h
+++ b/compiler-rt/lib/scudo/standalone/secondary.h
@@ -823,7 +823,11 @@ void MapAllocator<Config>::deallocate(const Options &Options, void *Ptr)
     Cache.store(Options, H->CommitBase, H->CommitSize,
                 reinterpret_cast<uptr>(H + 1), H->MemMap);
   } else {
-    unmap(H->MemMap);
+    // Note that the `H->MemMap` is stored on the pages managed by itself. Take
+    // over the ownership before unmap() so that any operation along with
+    // unmap() won't touch inaccessible pages.
+    MemMapT MemMap = H->MemMap;
+    unmap(MemMap);
   }
 }