7107135: Stack guard pages are no more protected after loading a shared library with executable stack
Summary: Detect the execstack attribute of the loaded library and attempt to fix the stack guard using Safepoint op.
Reviewed-by: dholmes, zgu
Contributed-by: ioi.lam@oracle.com
/*
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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class TestMT {
static boolean loadLib(String libName) {
try {
System.loadLibrary(libName);
System.out.println("Loaded library "+ libName + ".");
return true;
} catch (SecurityException e) {
System.out.println("loadLibrary(\"" + libName + "\") throws: " + e + "\n");
} catch (UnsatisfiedLinkError e) {
System.out.println("loadLibrary(\"" + libName + "\") throws: " + e + "\n");
}
return false;
}
public static int counter = 1;
static int Runner() {
counter = counter * -1;
int i = counter;
if (counter < 2) counter += Runner();
return i;
}
public static int run(String msg) {
try {
Runner();
} catch (StackOverflowError e) {
System.out.println(msg + " caught stack overflow error.");
return 0;
} catch (OutOfMemoryError e) {
return 0;
}
return 2;
}
public static void main(String argv[]) {
try {
for (int i = 0; i < 20; i++) {
Thread t = new DoStackOverflow("SpawnedThread " + i);
t.start();
}
run("Main thread");
loadLib("test-rwx");
run("Main thread");
} catch (Exception e) {
System.out.println(e);
}
}
static class DoStackOverflow extends Thread {
public DoStackOverflow(String name) {
super(name);
}
public void run() {
for (int i = 0; i < 10; ++i) {
TestMT.run(getName());
yield();
}
}
}
}