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Break recursive call of CacheVC::openReadStartEarliest #12710

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Merged
masaori335 merged 2 commits into from
Dec 10, 2025
Merged

Break recursive call of CacheVC::openReadStartEarliest #12710

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aa69855
Break recursive call of CacheVC::openReadStartEarliest
masaori335 Dec 1, 2025
9234c21
Address comments from Copilot
masaori335 Dec 4, 2025
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32 changes: 25 additions & 7 deletions src/iocore/cache/CacheRead.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,8 @@ DbgCtl dbg_ctl_cache_hit_evac{"cache_hit_evac"};

#endif

constexpr int MAX_READ_RECURSION_DEPTH = 10;

} // end anonymous namespace

uint32_t
Expand Down Expand Up @@ -749,8 +751,10 @@ Lread: {
int
CacheVC::openReadStartEarliest(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
{
int ret = 0;
Doc *doc = nullptr;
int call_result = 0;
int event_result = 0;
Doc *doc = nullptr;
bool is_recursive_call = false;
cancel_trigger();
set_io_not_in_progress();
if (_action.cancelled) {
Expand Down Expand Up @@ -815,10 +819,20 @@ CacheVC::openReadStartEarliest(int /* event ATS_UNUSED */, Event * /* e ATS_UNUS
if (stripe->directory.probe(&key, stripe, &earliest_dir, &last_collision) ||
dir_lookaside_probe(&key, stripe, &earliest_dir, nullptr)) {
dir = earliest_dir;
if ((ret = do_read_call(&key)) == EVENT_RETURN) {
if ((call_result = do_read_call(&key)) == EVENT_RETURN) {
if (this->handler == reinterpret_cast<ContinuationHandler>(&CacheVC::openReadStartEarliest)) {
is_recursive_call = true;
if (recursive > MAX_READ_RECURSION_DEPTH) {
char tmpstring[CRYPTO_HEX_SIZE];
Error("Too many recursive calls with %s", key.toHexStr(tmpstring));
goto Ldone;
}
++recursive;
}

goto Lcallreturn;
}
return ret;
return call_result;
}
// read has detected that alternate does not exist in the cache.
// rewrite the vector.
Expand Down Expand Up @@ -868,10 +882,10 @@ CacheVC::openReadStartEarliest(int /* event ATS_UNUSED */, Event * /* e ATS_UNUS
dir_set_tag(&od->single_doc_dir, od->single_doc_key.slice32(2));
}
SET_HANDLER(&CacheVC::openReadVecWrite);
if ((ret = do_write_call()) == EVENT_RETURN) {
if ((call_result = do_write_call()) == EVENT_RETURN) {
goto Lcallreturn;
}
return ret;
return call_result;
}
}
}
Expand All @@ -886,7 +900,11 @@ CacheVC::openReadStartEarliest(int /* event ATS_UNUSED */, Event * /* e ATS_UNUS
_action.continuation->handleEvent(CACHE_EVENT_OPEN_READ_FAILED, reinterpret_cast<void *>(-ECACHE_NO_DOC));
return free_CacheVC(this);
Lcallreturn:
return handleEvent(AIO_EVENT_DONE, nullptr); // hopefully a tail call
event_result = handleEvent(AIO_EVENT_DONE, nullptr); // hopefully a tail call
if (is_recursive_call) {
--recursive;
}
return event_result;
Lsuccess:
if (write_vc) {
ts::Metrics::Counter::increment(cache_rsb.read_busy_success);
Expand Down