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-rw-r--r--linux-user/main.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/linux-user/main.c b/linux-user/main.c
index 3597e99bb1..75c9785157 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -758,15 +758,27 @@ int main(int argc, char **argv, char **envp)
 
         if ((fp = fopen("/proc/sys/vm/mmap_min_addr", "r")) != NULL) {
             unsigned long tmp;
-            if (fscanf(fp, "%lu", &tmp) == 1) {
+            if (fscanf(fp, "%lu", &tmp) == 1 && tmp != 0) {
                 mmap_min_addr = tmp;
-                qemu_log_mask(CPU_LOG_PAGE, "host mmap_min_addr=0x%lx\n", mmap_min_addr);
+                qemu_log_mask(CPU_LOG_PAGE, "host mmap_min_addr=0x%lx\n",
+                              mmap_min_addr);
             }
             fclose(fp);
         }
     }
 
     /*
+     * We prefer to not make NULL pointers accessible to QEMU.
+     * If we're in a chroot with no /proc, fall back to 1 page.
+     */
+    if (mmap_min_addr == 0) {
+        mmap_min_addr = qemu_host_page_size;
+        qemu_log_mask(CPU_LOG_PAGE,
+                      "host mmap_min_addr=0x%lx (fallback)\n",
+                      mmap_min_addr);
+    }
+
+    /*
      * Prepare copy of argv vector for target.
      */
     target_argc = argc - optind;