Test to quickly reproduce bug #2471.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26247 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/tests/system/kernel/Jamfile

@@ -15,6 +15,8 @@ SimpleTest lock_node_test :
 	: be
 ;
 
+SimpleTest page_fault_cache_merge_test : page_fault_cache_merge_test.cpp ;
+
 SimpleTest port_close_test_1 : port_close_test_1.cpp ;
 SimpleTest port_close_test_2 : port_close_test_2.cpp ;
 

src/tests/system/kernel/page_fault_cache_merge_test.cpp

@@ -0,0 +1,59 @@
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <OS.h>
+
+
+static const int kAreaPagesCount = 4 * 1024;	// 16 MB
+
+
+int
+main()
+{
+	while (true) {
+		uint8* address;
+		area_id area = create_area("test area", (void**)&address, B_ANY_ADDRESS,
+			kAreaPagesCount * B_PAGE_SIZE, B_NO_LOCK,
+			B_READ_AREA | B_WRITE_AREA);
+		if (area < 0) {
+			fprintf(stderr, "Creating the area failed: %s", strerror(area));
+			exit(1);
+		}
+
+		// touch half of the pages
+		for (int i = 0; i < kAreaPagesCount / 2; i++)
+			address[i * B_PAGE_SIZE] = 42;
+
+		// fork
+		pid_t child = fork();
+		if (child < 0) {
+			perror("fork() failed");
+			exit(1);
+		}
+
+		if (child == 0) {
+			// child
+
+			// delete the copied area
+			delete_area(area_for(address));
+
+			exit(0);
+		}
+
+		// parent
+
+		// touch the other half of the pages
+		for (int i = kAreaPagesCount / 2; i < kAreaPagesCount; i++)
+			address[i * B_PAGE_SIZE] = 42;
+
+		int status;
+		while (wait(&status) != child);
+
+		delete_area(area);
+	}
+
+	return 0;
+}