[S390] kprobes: add parameter check to module_free()

When unregistering kprobes, kprobes calls module_free() and
always passes NULL for the mod parameter.  Add a check to
prevent NULL pointer dereferences.

See commit 740a8de0796dd12890b3c8ddcfabfcb528b78d40 for more details.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 639380a0c45c..22cfd634c355 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -55,8 +55,10 @@ void *module_alloc(unsigned long size)
 /* Free memory returned from module_alloc */
 void module_free(struct module *mod, void *module_region)
 {
-        vfree(mod->arch.syminfo);
-        mod->arch.syminfo = NULL;
+        if (mod) {
+                vfree(mod->arch.syminfo);
+                mod->arch.syminfo = NULL;
+        }
         vfree(module_region);
 }