From: Prarit Bhargava prarit@redhat.com
[ Upstream commit 6e6de3dee51a439f76eb73c22ae2ffd2c9384712 ]
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 Signed-off-by: Barret Rhoden brho@google.com Cc: David Arcari darcari@redhat.com Cc: Jessica Yu jeyu@kernel.org Cc: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Jessica Yu jeyu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/module.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c index 80c7c09584cf..8431c3d47c97 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3385,8 +3385,7 @@ static bool finished_loading(const char *name) sched_annotate_sleep(); mutex_lock(&module_mutex); mod = find_module_all(name, strlen(name), true); - ret = !mod || mod->state == MODULE_STATE_LIVE - || mod->state == MODULE_STATE_GOING; + ret = !mod || mod->state == MODULE_STATE_LIVE; mutex_unlock(&module_mutex);
return ret; @@ -3576,8 +3575,7 @@ 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,