Messages in this thread | | | Subject | Re: [PATCH] modules: Only return -EEXIST for modules that have finished loading | From | Prarit Bhargava <> | Date | Mon, 8 Apr 2019 10:19:52 -0400 |
| |
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 <prarit@redhat.com> > Reported-by: Cathy Avery <cavery@redhat.com> > Cc: Jessica Yu <jeyu@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, >
| |