Jessica? ping?
P.
On 4/2/19 9:39 AM, Prarit Bhargava wrote:
> Microsoft HyperV disables the X86_FEATURE_SMCA bit on AMD systems, and
> linux guests boot with repeated errors:
>
> amd64_edac_mod: Unknown symbol amd_unregister_ecc_decoder (err -2)
> amd64_edac_mod: Unknown symbol amd_register_ecc_decoder (err -2)
> amd64_edac_mod: Unknown symbol amd_report_gart_errors (err -2)
> amd64_edac_mod: Unknown symbol amd_unregister_ecc_decoder (err -2)
> amd64_edac_mod: Unknown symbol amd_register_ecc_decoder (err -2)
> amd64_edac_mod: Unknown symbol amd_report_gart_errors (err -2)
>
> The warnings occur because the module code erroneously returns -EEXIST
> for modules that have failed to load and are in the process of being
> removed from the module list.
>
> module amd64_edac_mod has a dependency on module edac_mce_amd. Using
> modules.dep, systemd will load edac_mce_amd for every request of
> amd64_edac_mod. When the edac_mce_amd module loads, the module has
> state MODULE_STATE_UNFORMED and once the module load fails and the state
> becomes MODULE_STATE_GOING. Another request for edac_mce_amd module
> executes and add_unformed_module() will erroneously return -EEXIST even
> though the previous instance of edac_mce_amd has MODULE_STATE_GOING.
> Upon receiving -EEXIST, systemd attempts to load amd64_edac_mod, which
> fails because of unknown symbols from edac_mce_amd.
>
> add_unformed_module() must wait to return for any case other than
> MODULE_STATE_LIVE to prevent a race between multiple loads of
> dependent modules.
>
> Signed-off-by: Prarit Bhargava <pra...@redhat.com>
> Reported-by: Cathy Avery <cav...@redhat.com>
> Cc: Jessica Yu <j...@kernel.org>
> ---
> kernel/module.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 0b9aa8ab89f0..e8c1de2ab4e1 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3566,8 +3566,7 @@ static int add_unformed_module(struct module *mod)
> mutex_lock(&module_mutex);
> old = find_module_all(mod->name, strlen(mod->name), true);
> if (old != NULL) {
> - if (old->state == MODULE_STATE_COMING
> - || old->state == MODULE_STATE_UNFORMED) {
> + if (old->state != MODULE_STATE_LIVE) {
> /* Wait in case it fails to load. */
> mutex_unlock(&module_mutex);
> err = wait_event_interruptible(module_wq,
>
