livepatch: Nullify obj->mod in klp_module_coming()'s error path

BugLink: https://bugs.launchpad.net/bugs/1848047
[ Upstream commit 4ff96fb52c6964ad42e0a878be8f86a2e8052ddd ]

klp_module_coming() is called for every module appearing in the system.
It sets obj->mod to a patched module for klp_object obj. Unfortunately
it leaves it set even if an error happens later in the function and the
patched module is not allowed to be loaded.

klp_is_object_loaded() uses obj->mod variable and could currently give a
wrong return value. The bug is probably harmless as of now.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index c4ce08f43bd63536793d47fd8bfa706ed511bbc2..ab4a4606d19b761caaabb82d39c632b37b0c3e3b 100644 (file)
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -1175,6 +1175,7 @@ err:
        pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
                patch->mod->name, obj->mod->name, obj->mod->name);
        mod->klp_alive = false;
+       obj->mod = NULL;
        klp_cleanup_module_patches_limited(mod, patch);
        mutex_unlock(&klp_mutex);