Changeset 38187 in webkit

Timestamp:

Nov 6, 2008 10:47:44 AM (15 years ago)

Author:

alp@webkit.org

Message:

2008-11-06 Alp Toker <​alp@nuanti.com>

Reviewed by Cameron Zwarich.

​https://bugs.webkit.org/show_bug.cgi?id=22033
[GTK] CTI/Linux r38064 crashes; JIT requires executable memory

Mark pages allocated by the FastMalloc mmap code path executable with
PROT_EXEC. This fixes crashes seen on CPUs and kernels that enforce
non-executable memory (like ExecShield on Fedora Linux) when the JIT
is enabled.

This patch does not resolve the issue on debug builds so affected
developers may still need to pass --disable-jit to configure.

• wtf/TCSystemAlloc.cpp: (TryMmap): (TryDevMem): (TCMalloc_SystemRelease):

Location:

trunk/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• wtf/TCSystemAlloc.cpp (modified) (4 diffs)

trunk/JavaScriptCore/ChangeLog

@@ +1 @@
+2008-11-06  Alp Toker  <alp@nuanti.com>
+
+        Reviewed by Cameron Zwarich.
+
+        https://bugs.webkit.org/show_bug.cgi?id=22033
+        [GTK] CTI/Linux r38064 crashes; JIT requires executable memory
+
+        Mark pages allocated by the FastMalloc mmap code path executable with
+        PROT_EXEC. This fixes crashes seen on CPUs and kernels that enforce
+        non-executable memory (like ExecShield on Fedora Linux) when the JIT
+        is enabled.
+
+        This patch does not resolve the issue on debug builds so affected
+        developers may still need to pass --disable-jit to configure.
+
+        * wtf/TCSystemAlloc.cpp:
+        (TryMmap):
+        (TryDevMem):
+        (TCMalloc_SystemRelease):
+
 2008-11-06  Peter Gal  <galpeter@inf.u-szeged.hu>
 

trunk/JavaScriptCore/wtf/TCSystemAlloc.cpp

@@ -52 +52 @@
 #include "UnusedParam.h"
 
+#if HAVE(MMAP)
+static const int cProtFlags = PROT_READ | PROT_WRITE
+#if ENABLE(CTI) && PLATFORM(GTK)
+                              | PROT_EXEC
+#endif
+                              ;
+#endif
+
 #ifndef MAP_ANONYMOUS
 #define MAP_ANONYMOUS MAP_ANON
@@ -171 +179 @@
   }
   void* result = mmap(NULL, size + extra,
-                      PROT_READ|PROT_WRITE,
+                      cProtFlags,
                       MAP_PRIVATE|MAP_ANONYMOUS,
                       -1, 0);
@@ -303 +311 @@
     return NULL;
   }
-  void *result = mmap(0, size + extra, PROT_WRITE|PROT_READ,
+  void *result = mmap(0, size + extra, cProtFlags,
                       MAP_SHARED, physmem_fd, physmem_base);
   if (result == reinterpret_cast<void*>(MAP_FAILED)) {
@@ -422 +430 @@
 
 #if HAVE(MMAP)
-  void *newAddress = mmap(start, length, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
+  void *newAddress = mmap(start, length, cProtFlags, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
   UNUSED_PARAM(newAddress);
   // If the mmap failed then that's ok, we just won't return the memory to the system.