Title: [92635] trunk/Source/_javascript_Core
- Revision
- 92635
- Author
- [email protected]
- Date
- 2011-08-08 14:28:53 -0700 (Mon, 08 Aug 2011)
Log Message
Using mprotect to create guard pages breaks our use of madvise to release executable memory
https://bugs.webkit.org/show_bug.cgi?id=65870
Reviewed by Gavin Barraclough.
Use mmap rather than mprotect to clear guard page permissions.
* wtf/OSAllocatorPosix.cpp:
(WTF::OSAllocator::reserveAndCommit):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (92634 => 92635)
--- trunk/Source/_javascript_Core/ChangeLog 2011-08-08 21:28:03 UTC (rev 92634)
+++ trunk/Source/_javascript_Core/ChangeLog 2011-08-08 21:28:53 UTC (rev 92635)
@@ -1,5 +1,17 @@
2011-08-08 Oliver Hunt <[email protected]>
+ Using mprotect to create guard pages breaks our use of madvise to release executable memory
+ https://bugs.webkit.org/show_bug.cgi?id=65870
+
+ Reviewed by Gavin Barraclough.
+
+ Use mmap rather than mprotect to clear guard page permissions.
+
+ * wtf/OSAllocatorPosix.cpp:
+ (WTF::OSAllocator::reserveAndCommit):
+
+2011-08-08 Oliver Hunt <[email protected]>
+
Non-extensibility does not prevent mutating [[Prototype]]
https://bugs.webkit.org/show_bug.cgi?id=65832
Modified: trunk/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp (92634 => 92635)
--- trunk/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp 2011-08-08 21:28:03 UTC (rev 92634)
+++ trunk/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp 2011-08-08 21:28:53 UTC (rev 92635)
@@ -104,8 +104,12 @@
CRASH();
}
if (result && includesGuardPages) {
- mprotect(result, pageSize(), PROT_NONE);
- mprotect(static_cast<char*>(result) + bytes - pageSize(), pageSize(), PROT_NONE);
+ // We use mmap to remap the guardpages rather than using mprotect as
+ // mprotect results in multiple references to the code region. This
+ // breaks the madvise based mechanism we use to return physical memory
+ // to the OS.
+ mmap(result, pageSize(), PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, fd, 0);
+ mmap(static_cast<char*>(result) + bytes - pageSize(), pageSize(), PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, fd, 0);
}
return result;
}
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