From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Wed, 26 Oct 2011 22:48:10 +0000 (-0700)
Subject: test - Add code to test recent bus error issue
X-Git-Tag: v3.0.0~811
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/1c60bab9b3f5ce8531f1c2117542d42c2262569d

test - Add code to test recent bus error issue

Submitted-by: "Samuel J. Greear" <sjg@evilcode.net>
---

diff --git a/test/debug/buserr.c b/test/debug/buserr.c
new file mode 100644
index 0000000000..c7dfb4205a
--- /dev/null
+++ b/test/debug/buserr.c
@@ -0,0 +1,59 @@
+/*
+ * Test a fork/munmap vm_object shadow chain race
+ *
+ * Written by "Samuel J. Greear" <sjg@evilcode.net>
+ */
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <sys/wait.h>
+
+#define MAPPING_PAGES   4096
+
+int
+main(int argc, char *argv[])
+{
+    unsigned int i, size;
+    int status;
+    pid_t pid;
+    void *mapping;
+    char tmp[100];
+
+    for (i = 1; i < MAPPING_PAGES; ++i) {
+        size = PAGE_SIZE * i;
+        mapping = mmap(0, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED,
+		       -1, 0);
+        if (mapping == MAP_FAILED)
+            errx(EX_OSERR, "mmap() failed");
+
+        memset(mapping, 'x', 10);
+	printf(" %d", i);
+	fflush(stdout);
+
+        pid = fork();
+        if (pid == 0) {
+            memcpy(&tmp, mapping, 12);
+            return (0);
+        } else if (pid != -1) {
+            if (munmap(mapping, PAGE_SIZE * i) != 0) {
+                printf("munmap failed\n");
+                return (0);
+            }
+            waitpid(pid, &status, 0);
+            if (status == 10) {
+                printf("child sig10 at %d pages\n", i);
+                return (0);
+            }
+        } else {
+            printf("fork failed\n");
+        }
+    }
+
+    return (0);
+}