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avoid crash when rescheduling timers from callback (#356) #361

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avoid crash when rescheduling timers from callback (#356) #361

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81 changes: 43 additions & 38 deletions code/common/src/timer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,10 +13,10 @@
* Set timer expiration.
*/
static void
timer_set_expire(timer_s *timer, time_t sec, long nsec)
timer_set_expire(timer_s *timer)
{
timer->expire.tv_sec += sec;
timer->expire.tv_nsec += nsec;
timer->expire.tv_sec += timer->sec;
timer->expire.tv_nsec += timer->nsec;

/* Handle nsec overflow. */
if(timer->expire.tv_nsec >= 1e9) {
Expand Down Expand Up @@ -84,7 +84,6 @@ timespec_add(struct timespec *result, struct timespec *x, struct timespec *y)
void
timespec_sub(struct timespec *result, struct timespec *x, struct timespec *y)
{

if(x->tv_sec < y->tv_sec) {
result->tv_sec = 0;
result->tv_nsec = 0;
Expand Down Expand Up @@ -144,13 +143,13 @@ timer_change(timer_s *timer)
}

static void
timer_enqueue_bucket(timer_root_s *root, timer_s *timer, time_t sec, long nsec)
timer_enqueue_bucket(timer_root_s *root, timer_s *timer)
{
timer_bucket_s *timer_bucket;

/* Find the bucket for insertion. */
CIRCLEQ_FOREACH(timer_bucket, &root->timer_bucket_qhead, timer_bucket_qnode) {
if(timer_bucket->sec != sec || timer_bucket->nsec != nsec) {
if(timer_bucket->sec != timer->sec || timer_bucket->nsec != timer->nsec) {
continue;
}
/* Found it! */
Expand All @@ -166,8 +165,8 @@ timer_enqueue_bucket(timer_root_s *root, timer_s *timer, time_t sec, long nsec)

CIRCLEQ_INSERT_TAIL(&root->timer_bucket_qhead, timer_bucket, timer_bucket_qnode);
CIRCLEQ_INIT(&timer_bucket->timer_qhead);
timer_bucket->sec = sec;
timer_bucket->nsec = nsec;
timer_bucket->sec = timer->sec;
timer_bucket->nsec = timer->nsec;
timer_bucket->timer_root = root;
root->buckets++;

Expand Down Expand Up @@ -214,31 +213,31 @@ timer_dequeue_bucket(timer_s *timer)
}

static void
timer_requeue(timer_s *timer, time_t sec, long nsec)
timer_requeue(timer_s *timer)
{
timer_root_s *timer_root;
timer_bucket_s *timer_bucket;

timer_bucket = timer->timer_bucket;
timer_root = timer_bucket->timer_root;

timer_set_expire(timer, sec, nsec);
timer_set_expire(timer);

/* If the expiration {sec,nsec} matches the bucket, then simply
* timer dequeue and enqueue to keep correct temporal ordering.
* If there is no match, do a slightly more expensive
* bucket dequeue and enqueue. */
if(timer_bucket->sec == sec && timer_bucket->nsec == nsec) {
if(timer_bucket->sec == timer->sec && timer_bucket->nsec == timer->nsec) {
CIRCLEQ_REMOVE(&timer_bucket->timer_qhead, timer, timer_qnode);
CIRCLEQ_INSERT_TAIL(&timer_bucket->timer_qhead, timer, timer_qnode);
} else {
timer_dequeue_bucket(timer);
timer_enqueue_bucket(timer_root, timer, sec, nsec);
timer_enqueue_bucket(timer_root, timer);
}

#ifdef BNGBLASTER_TIMER_LOGGING
LOG(TIMER_DETAIL, " Reset %s timer, expire in %lu.%06lus\n",
timer->name, sec, nsec/1000);
timer->name, timer->sec, timer->nsec/1000);
#endif

}
Expand Down Expand Up @@ -354,17 +353,12 @@ timer_del(timer_s *timer)
* Deferred processing of all timers.
*/
static void
timer_process_changes(timer_root_s *root)
timer_process_changes(timer_root_s *root, struct timespec *now)
{
timer_s *timer;
timer_bucket_s *timer_bucket;

struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);

while(!CIRCLEQ_EMPTY(&root->timer_change_qhead)) {
timer = CIRCLEQ_FIRST(&root->timer_change_qhead);
timer_bucket = timer->timer_bucket;

/* Changes are only processed once.
* Take this timer off the change list. */
Expand All @@ -377,16 +371,15 @@ timer_process_changes(timer_root_s *root)
continue;
}

if(timer->periodic) {
/* Requeue. */
if(timer->reset) {
/* Reset timer start time. */
timer->expire.tv_sec = now.tv_sec;
timer->expire.tv_nsec = now.tv_nsec;
}
timer_requeue(timer, timer_bucket->sec, timer_bucket->nsec);
continue;
/* Handle Periodic or Rescheduled Timers */
/* If it's periodic, we might need to reset start time */
if(timer->periodic && timer->reset) {
/* Reset timer start time. */
timer->expire.tv_sec = now->tv_sec;
timer->expire.tv_nsec = now->tv_nsec;
}

timer_requeue(timer);
}
}

Expand All @@ -404,14 +397,21 @@ timer_add(timer_root_s *root, timer_s **ptimer, char *name,
/* This timer already is enqueued. Requeue. */
if(timer) {
clock_gettime(CLOCK_MONOTONIC, &timer->expire);
timer_requeue(timer, sec, nsec);

/* Update data and cb if there was a change.
* Do the reformatting of name only during a change. */
if(timer->data != data || timer->cb != cb) {
strncpy(timer->name, name, sizeof(timer->name)-1);
timer->data = data;
timer->cb = cb;
}
timer->expired = false;
timer->periodic = false;
timer->reset = false;
timer->delete = false;
timer->sec = sec;
timer->nsec = nsec;
timer_change(timer);
return;
}

Expand All @@ -434,13 +434,15 @@ timer_add(timer_root_s *root, timer_s **ptimer, char *name,
strncpy(timer->name, name, sizeof(timer->name)-1);
timer->data = data;
timer->cb = cb;
timer->sec = sec;
timer->nsec = nsec;
clock_gettime(CLOCK_MONOTONIC, &timer->expire);
timer_set_expire(timer, sec, nsec);
timer_set_expire(timer);
timer->ptimer = ptimer;
*ptimer = timer;

/* Enqueue it into the correct timer bucket. */
timer_enqueue_bucket(root, timer, sec, nsec);
timer_enqueue_bucket(root, timer);

#ifdef BNGBLASTER_TIMER_LOGGING
LOG(TIMER, "Add %s timer, expire in %lu.%06lus\n", timer->name, sec, nsec/1000);
Expand Down Expand Up @@ -508,6 +510,11 @@ timer_walk(timer_root_s *root)
break;
}

/* Skip timers on change list. */
if(timer->on_change_list) {
continue;
}

/* Everything from here one is expired. */
timer->expired = true;

Expand All @@ -532,17 +539,12 @@ timer_walk(timer_root_s *root)
}

/* Process all changes from the last timer run. */
timer_process_changes(root);
timer_process_changes(root, &now);

/* Second pass. Figure out min sleep time. */
CIRCLEQ_FOREACH(timer_bucket, &root->timer_bucket_qhead, timer_bucket_qnode) {
CIRCLEQ_FOREACH(timer, &timer_bucket->timer_qhead, timer_qnode) {

/* Ignore deleted timers that wait for change processing. */
if(timer->delete) {
continue;
}

/* First timer in the queue becomes the actual minimum. */
if(min.tv_sec == 0 && min.tv_nsec == 0) {
min.tv_sec = timer->expire.tv_sec;
Expand All @@ -558,6 +560,7 @@ timer_walk(timer_root_s *root)
timer->name, min.tv_sec, min.tv_nsec / 1000);
#endif
}

/* Hitting the first non-expired timer means
* we're done processing this buckets queue. */
if(timespec_compare(&timer->expire, &now) == 1) {
Expand Down Expand Up @@ -613,14 +616,16 @@ timer_flush_root(timer_root_s *timer_root)
{
timer_s *timer;
timer_bucket_s *timer_bucket;
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);

/* First step. Walk all timers and move them onto the GC thread. */
CIRCLEQ_FOREACH(timer_bucket, &timer_root->timer_bucket_qhead, timer_bucket_qnode) {
CIRCLEQ_FOREACH(timer, &timer_bucket->timer_qhead, timer_qnode) {
timer_del(timer);
}
}
timer_process_changes(timer_root);
timer_process_changes(timer_root, &now);

/* Second step. Run the GC queue. */
while(!CIRCLEQ_EMPTY(&timer_root->timer_gc_qhead)) {
Expand Down
2 changes: 2 additions & 0 deletions code/common/src/timer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,8 @@ typedef struct timer_
bool delete; /* timer has been deleted */
bool on_change_list; /* node is on change list */
char name[32];
time_t sec;
long nsec;
} timer_s;

/* Public API */
Expand Down
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