module: prevent warning when finit_module a 0 sized file

If we try to finit_module on a file sized 0 bytes vmalloc will
scream and spit out a warning.

Since modules have to be bigger than 0 bytes anyways we can just
check that beforehand and avoid the warning.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 7 insertions, 0 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 250092c1d57d..41bc1189b061 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2527,6 +2527,13 @@ static int copy_module_from_fd(int fd, struct load_info *info)
                 err = -EFBIG;
                 goto out;
         }
+
+        /* Don't hand 0 to vmalloc, it whines. */
+        if (stat.size == 0) {
+                err = -EINVAL;
+                goto out;
+        }
+
         info->hdr = vmalloc(stat.size);
         if (!info->hdr) {
                 err = -ENOMEM;