From: Jiri Kosina <jkos...@suse.cz>

Commit 425595a7fc20 ("livepatch: reuse module loader code to write 
relocations") adds a possibility of dereferncing pointers supplied by the 
consumer of the livepatch API before sanity (NULL) checking them (patch 
and patch->mod).

Spotted by smatch tool.

Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Jiri Kosina <jkos...@suse.cz>
---
 kernel/livepatch/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index eb5db6e..28c37fa 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -876,6 +876,9 @@ int klp_register_patch(struct klp_patch *patch)
 {
        int ret;
 
+       if (!patch || !patch->mod)
+               return -EINVAL;
+
        if (!is_livepatch_module(patch->mod)) {
                pr_err("module %s is not marked as a livepatch module",
                       patch->mod->name);
@@ -885,9 +888,6 @@ int klp_register_patch(struct klp_patch *patch)
        if (!klp_initialized())
                return -ENODEV;
 
-       if (!patch || !patch->mod)
-               return -EINVAL;
-
        /*
         * A reference is taken on the patch module to prevent it from being
         * unloaded.  Right now, we don't allow patch modules to unload since

-- 
Jiri Kosina
SUSE Labs

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