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main/cdr.c: Alleviate CDR deadlock

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There is a rare case (do to the infrequent timing involved) where
CDR submission threads in batch mode can deadlock with a currently
running CDR batch process.  This patch should remove the need for
holding the lock in the scheduler and should clean a few code
paths up that inconsistently submitted new work to the CDR batch
processor.

ASTERISK-27909

Change-Id: I6333e865db7c593c102c2fd948cecdb96481974d
Reported-by: Denis Lebedev
This commit is contained in:
Matthew Fredrickson
2018-06-21 00:28:01 -05:00
committed by Joshua Colp
parent 5f517bacd0
commit db02218db2
1 changed files with 16 additions and 19 deletions
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35
main/cdr.c
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@@ -3785,6 +3785,7 @@ static void cdr_submit_batch(int do_shutdown)
static int submit_scheduled_batch(const void *data)
{
struct module_config *mod_cfg;
int nextms;
cdr_submit_batch(0);
@@ -3793,25 +3794,23 @@ static int submit_scheduled_batch(const void *data)
return 0;
}
/* manually reschedule from this point in time */
ast_mutex_lock(&cdr_sched_lock);
cdr_sched = ast_sched_add(sched, mod_cfg->general->batch_settings.time * 1000, submit_scheduled_batch, NULL);
ast_mutex_unlock(&cdr_sched_lock);
/* Calculate the next scheduled interval */
nextms = mod_cfg->general->batch_settings.time * 1000;
ao2_cleanup(mod_cfg);
/* returning zero so the scheduler does not automatically reschedule */
return 0;
return nextms;
}
/*! Do not hold the batch lock while calling this function */
static void submit_unscheduled_batch(void)
static void start_batch_mode(void)
{
/* Prevent two deletes from happening at the same time */
ast_mutex_lock(&cdr_sched_lock);
/* this is okay since we are not being called from within the scheduler */
AST_SCHED_DEL(sched, cdr_sched);
/* schedule the submission to occur ASAP (1 ms) */
cdr_sched = ast_sched_add(sched, 1, submit_scheduled_batch, NULL);
cdr_sched = ast_sched_add_variable(sched, 1, submit_scheduled_batch, NULL, 1);
ast_mutex_unlock(&cdr_sched_lock);
/* signal the do_cdr thread to wakeup early and do some work (that lazy thread ;) */
@@ -3876,9 +3875,9 @@ static void cdr_detach(struct ast_cdr *cdr)
}
ast_mutex_unlock(&cdr_batch_lock);
/* Don't call submit_unscheduled_batch with the cdr_batch_lock held */
/* Don't submit a batch with cdr_batch_lock held */
if (submit_batch) {
submit_unscheduled_batch();
start_batch_mode();
}
}
@@ -3892,7 +3891,7 @@ static void *do_cdr(void *data)
struct timeval now;
schedms = ast_sched_wait(sched);
/* this shouldn't happen, but provide a 1 second default just in case */
if (schedms <= 0)
if (schedms < 0)
schedms = 1000;
now = ast_tvadd(ast_tvnow(), ast_samp2tv(schedms, 1000));
timeout.tv_sec = now.tv_sec;
@@ -3902,7 +3901,7 @@ static void *do_cdr(void *data)
ast_cond_timedwait(&cdr_pending_cond, &cdr_pending_lock, &timeout);
numevents = ast_sched_runq(sched);
ast_mutex_unlock(&cdr_pending_lock);
ast_debug(2, "Processed %d scheduled CDR batches from the run queue\n", numevents);
ast_debug(2, "Processed %d CDR batches from the run queue\n", numevents);
}
return NULL;
@@ -4220,7 +4219,7 @@ static char *handle_cli_submit(struct ast_cli_entry *e, int cmd, struct ast_cli_
} else if (!ast_test_flag(&mod_cfg->general->settings, CDR_BATCHMODE)) {
ast_cli(a->fd, "Cannot submit CDR batch: batch mode not enabled.\n");
} else {
submit_unscheduled_batch();
start_batch_mode();
ast_cli(a->fd, "Submitted CDRs to backend engines for processing. This may take a while.\n");
}
ao2_cleanup(mod_cfg);
@@ -4336,7 +4335,7 @@ static int process_config(int reload)
aco_option_register(&cfg_info, "scheduleronly", ACO_EXACT, general_options, DEFAULT_BATCH_SCHEDULER_ONLY, OPT_BOOLFLAG_T, 1, FLDSET(struct ast_cdr_config, batch_settings.settings), BATCH_MODE_SCHEDULER_ONLY);
aco_option_register(&cfg_info, "safeshutdown", ACO_EXACT, general_options, DEFAULT_BATCH_SAFE_SHUTDOWN, OPT_BOOLFLAG_T, 1, FLDSET(struct ast_cdr_config, batch_settings.settings), BATCH_MODE_SAFE_SHUTDOWN);
aco_option_register(&cfg_info, "size", ACO_EXACT, general_options, DEFAULT_BATCH_SIZE, OPT_UINT_T, PARSE_IN_RANGE, FLDSET(struct ast_cdr_config, batch_settings.size), 0, MAX_BATCH_SIZE);
aco_option_register(&cfg_info, "time", ACO_EXACT, general_options, DEFAULT_BATCH_TIME, OPT_UINT_T, PARSE_IN_RANGE, FLDSET(struct ast_cdr_config, batch_settings.time), 0, MAX_BATCH_TIME);
aco_option_register(&cfg_info, "time", ACO_EXACT, general_options, DEFAULT_BATCH_TIME, OPT_UINT_T, PARSE_IN_RANGE, FLDSET(struct ast_cdr_config, batch_settings.time), 1, MAX_BATCH_TIME);
}
if (aco_process_config(&cfg_info, reload) == ACO_PROCESS_ERROR) {
@@ -4397,8 +4396,6 @@ static void cdr_engine_shutdown(void)
static void cdr_enable_batch_mode(struct ast_cdr_config *config)
{
SCOPED_LOCK(batch, &cdr_batch_lock, ast_mutex_lock, ast_mutex_unlock);
/* Only create the thread level portions once */
if (cdr_thread == AST_PTHREADT_NULL) {
ast_cond_init(&cdr_pending_cond, NULL);
@@ -4408,9 +4405,9 @@ static void cdr_enable_batch_mode(struct ast_cdr_config *config)
}
}
/* Kill the currently scheduled item */
AST_SCHED_DEL(sched, cdr_sched);
cdr_sched = ast_sched_add(sched, config->batch_settings.time * 1000, submit_scheduled_batch, NULL);
/* Start the batching process */
start_batch_mode();
ast_log(LOG_NOTICE, "CDR batch mode logging enabled, first of either size %u or time %u seconds.\n",
config->batch_settings.size, config->batch_settings.time);
}