diff mbox series

[v2,09/13] migration: Check in savevm_state_handler_insert for dups

Message ID 20231020090731.28701-10-quintela@redhat.com (mailing list archive)
State New, archived
Headers show
Series migration: Check for duplicates on vmstate_register() | expand

Commit Message

Juan Quintela Oct. 20, 2023, 9:07 a.m. UTC 
From: Peter Xu <peterx@redhat.com>

Before finally register one SaveStateEntry, we detect for duplicated
entries.  This could be helpful to notify us asap instead of get
silent migration failures which could be hard to diagnose.

For example, this patch will generate a message like this (if without
previous fixes on x2apic) as long as we wants to boot a VM instance
with "-smp 200,maxcpus=288,sockets=2,cores=72,threads=2" and QEMU will
bail out even before VM starts:

savevm_state_handler_insert: Detected duplicate SaveStateEntry: id=apic, instance_id=0x0

Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/savevm.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
diff mbox series

Patch

diff --git a/migration/savevm.c b/migration/savevm.c
index d3a30686d4..3e0ece84e8 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -237,6 +237,8 @@  static SaveState savevm_state = {
     .global_section_id = 0,
 };
 
+static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id);
+
 static bool should_validate_capability(int capability)
 {
     assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX);
@@ -716,6 +718,18 @@  static void savevm_state_handler_insert(SaveStateEntry *nse)
 
     assert(priority <= MIG_PRI_MAX);
 
+    /*
+     * This should never happen otherwise migration will probably fail
+     * silently somewhere because we can be wrongly applying one
+     * object properties upon another one.  Bail out ASAP.
+     */
+    if (find_se(nse->idstr, nse->instance_id)) {
+        error_report("%s: Detected duplicate SaveStateEntry: "
+                     "id=%s, instance_id=0x%"PRIx32, __func__,
+                     nse->idstr, nse->instance_id);
+        exit(EXIT_FAILURE);
+    }
+
     for (i = priority - 1; i >= 0; i--) {
         se = savevm_state.handler_pri_head[i];
         if (se != NULL) {