[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 <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>

diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 639380a0c45c6278db26a03ea7b39eeec8fc48f2..22cfd634c35531b7f8a1d4057f92b4af72e20d1a 100644 (file)
--- 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);
 }