From: Daniel Gomez The -EEXIST error code is reserved by the module loading infrastructure to indicate that a module is already loaded. When a module's init function returns -EEXIST, userspace tools like kmod interpret this as "module already loaded" and treat the operation as successful, returning 0 to the user even though the module initialization actually failed. This follows the precedent set by commit 54416fd76770 ("netfilter: conntrack: helper: Replace -EEXIST by -EBUSY") which fixed the same issue in nf_conntrack_helper_register(). This affects bpf_crypto_skcipher module. While the configuration required to build it as a module is unlikely in practice, it is technically possible, so fix it for correctness. Signed-off-by: Daniel Gomez --- The error code -EEXIST is reserved by the kernel module loader to indicate that a module with the same name is already loaded. When a module's init function returns -EEXIST, kmod interprets this as "module already loaded" and reports success instead of failure [1]. The kernel module loader will include a safety net that provides -EEXIST to -EBUSY with a warning [2], and a documentation patch has been sent to prevent future occurrences [3]. These affected code paths were identified using a static analysis tool [4] that traces -EEXIST returns to module_init(). The tool was developed with AI assistance and all findings were manually validated. Link: https://lore.kernel.org/all/aKEVQhJpRdiZSliu@orbyte.nwl.cc/ [1] Link: https://lore.kernel.org/all/20251013-module-warn-ret-v1-0-ab65b41af01f@intel.com/ [2] Link: https://lore.kernel.org/all/20251218-dev-module-init-eexists-modules-docs-v1-0-361569aa782a@samsung.com/ [3] Link: https://gitlab.com/-/snippets/4913469 [4] --- kernel/bpf/crypto.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/crypto.c b/kernel/bpf/crypto.c index 83c4d9943084..1ab79a6dec84 100644 --- a/kernel/bpf/crypto.c +++ b/kernel/bpf/crypto.c @@ -60,7 +60,7 @@ struct bpf_crypto_ctx { int bpf_crypto_register_type(const struct bpf_crypto_type *type) { struct bpf_crypto_type_list *node; - int err = -EEXIST; + int err = -EBUSY; down_write(&bpf_crypto_types_sem); list_for_each_entry(node, &bpf_crypto_types, list) { --- base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 change-id: 20251219-dev-module-init-eexists-bpf-da2aa3577437 Best regards, -- Daniel Gomez