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authorPeter Xu <peterx@redhat.com>2023-10-20 11:07:27 +0200
committerJuan Quintela <quintela@redhat.com>2023-11-01 16:13:58 +0100
commitcaa91b3c44cdb2d2921e25eda554d38c527e6c47 (patch)
tree55260445480d222b719adf5add604ea7547bd26b
parent485fb95546e1cc94e77b93ff785bdbfa2c1d3ff1 (diff)
downloadfocaccia-qemu-caa91b3c44cdb2d2921e25eda554d38c527e6c47.tar.gz
focaccia-qemu-caa91b3c44cdb2d2921e25eda554d38c527e6c47.zip
migration: Check in savevm_state_handler_insert for dups
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>
Message-ID: <20231020090731.28701-10-quintela@redhat.com>
-rw-r--r--migration/savevm.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/migration/savevm.c b/migration/savevm.c
index c7596c3e9b..2095ddd6f8 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) {