From caa91b3c44cdb2d2921e25eda554d38c527e6c47 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 20 Oct 2023 11:07:27 +0200 Subject: [PATCH] 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 Signed-off-by: Peter Xu Reviewed-by: Juan Quintela Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Juan Quintela Message-ID: <20231020090731.28701-10-quintela@redhat.com> --- migration/savevm.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) 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) {