Commit 389775d1 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Juan Quintela
Browse files

migration_init: Fix lock initialisation/make it explicit 



Peter reported a lock error on MacOS after my a82d593b
patch.

migrate_get_current does one-time initialisation of
a bunch of variables.
migrate_init does reinitialisation even on a 2nd
migrate after a cancel.

The problem here was that I'd initialised the mutex
in migrate_get_current, and the memset in migrate_init
corrupted it.

Remove the memset and replace it by explicit initialisation
of fields that need initialising; this also turns out to be simpler
than the old code that had to preserve some fields.

Reported-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Fixes: a82d593b
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent a54d340b

migration/migration.c

+23 −30
Original line number Diff line number Diff line
@@ -902,38 +902,31 @@ bool migration_in_postcopy(MigrationState *s) 
MigrationState *migrate_init(const MigrationParams *params)

{

    MigrationState *s = migrate_get_current();

    int64_t bandwidth_limit = s->bandwidth_limit;

    bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];

    int64_t xbzrle_cache_size = s->xbzrle_cache_size;

    int compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];

    int compress_thread_count =

            s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];

    int decompress_thread_count =

            s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];

    int x_cpu_throttle_initial =

            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];

    int x_cpu_throttle_increment =

            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];



    memcpy(enabled_capabilities, s->enabled_capabilities,

           sizeof(enabled_capabilities));



    memset(s, 0, sizeof(*s));

    /*

     * Reinitialise all migration state, except

     * parameters/capabilities that the user set, and

     * locks.

     */

    s->bytes_xfer = 0;

    s->xfer_limit = 0;

    s->cleanup_bh = 0;

    s->file = NULL;

    s->state = MIGRATION_STATUS_NONE;

    s->params = *params;

    memcpy(s->enabled_capabilities, enabled_capabilities,

           sizeof(enabled_capabilities));

    s->xbzrle_cache_size = xbzrle_cache_size;

    s->rp_state.from_dst_file = NULL;

    s->rp_state.error = false;

    s->mbps = 0.0;

    s->downtime = 0;

    s->expected_downtime = 0;

    s->dirty_pages_rate = 0;

    s->dirty_bytes_rate = 0;

    s->setup_time = 0;

    s->dirty_sync_count = 0;

    s->start_postcopy = false;

    s->migration_thread_running = false;

    s->last_req_rb = NULL;



    s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;

    s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =

               compress_thread_count;

    s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =

               decompress_thread_count;

    s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =

                x_cpu_throttle_initial;

    s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =

                x_cpu_throttle_increment;

    s->bandwidth_limit = bandwidth_limit;

    migrate_set_state(s, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);



    QSIMPLEQ_INIT(&s->src_page_requests);