| From c23a7a90d5430fdc30464bf36258b9d338071835 Mon Sep 17 00:00:00 2001 |
| From: Prarit Bhargava <prarit@redhat.com> |
| Date: Wed, 29 May 2019 07:26:25 -0400 |
| Subject: kernel/module.c: Only return -EEXIST for modules that have finished |
| loading |
| |
| [ 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 2325c9821f2a1..fb9e07aec49e0 100644 |
| --- a/kernel/module.c |
| +++ b/kernel/module.c |
| @@ -3351,8 +3351,7 @@ 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; |
| @@ -3515,8 +3514,7 @@ again: |
| 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, |
| -- |
| 2.20.1 |
| |