Re: [PATCH] KEYS: replace -EEXIST with -EBUSY

[David Howells <dhowells@redhat.com>]

Daniel Gomez <da.gomez@kernel.org> wrote:

> From: Daniel Gomez <da.gomez@samsung.com>
> 
> The -EEXIST error code is reserved by the module loading infrastructure
> to indicate that a module is already loaded.

EEXIST means a file exists when you're trying to create it.  Granted we abuse
that somewhat rather than add ever more error codes, but you cannot reserve it
for indicating that a module exists.

> 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().
> 
> Affected modules:
>   * pkcs8_key_parser x509_key_parser asymmetric_keys dns_resolver
>   * nvme_keyring pkcs7_test_key rxrpc turris_signing_key
> 
> Signed-off-by: Daniel Gomez <da.gomez@samsung.com>

Please don't.  Userspace can always check /proc/modules (assuming procfs is
enabled, I suppose).

David