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CI Test Results

Run: #37651377726 | Commit: a2d6179 | Duration: 17m 37s (longest job)

✅ All 32 test jobs passed

Status Overview

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Summary: Total: 32 | Passed: 32 | Failed: 0

Updated: 2026-10-07 16:43:58 UTC

✅ All 40 integration tests passed

📊 Dashboard · 👷 Pipeline · 📦 26e27c07

ddprof-lib/src/main/cpp/callTraceStorage.cpp:82

[Sphinx Review — MEDIUM] The destructor CallTraceStorage::~CallTraceStorage() was modified to conditionally delete standby only when waitForRefCountToClear(standby) returns true. The new test ClearWithGuardHeldLeaksChunks tests CallTraceHashTable::clearTableOnly() but never instantiates or destroys a CallTraceStorage object. A mutation flipping the condition (if (!RefCountGuard::waitForRefCountToClear(standby))) or removing the delete statement would not be caught by any test in this diff.

Suggestion: Add a test that instantiates CallTraceStorage, holds a RefCountGuard to force a drain timeout, then destroys the CallTraceStorage to verify the conditional-delete logic is correct. This would catch mutations of the condition or deletion of the delete statement.

This is more important now when we will need to be able to turn on/off profiler while the process is still alive

ddprof-lib/src/main/cpp/callTraceStorage.cpp:85

[Sphinx Review — MEDIUM] The destructor CallTraceStorage::~CallTraceStorage() was modified to conditionally delete scratch only when waitForRefCountToClear(scratch) returns true. The new test ClearWithGuardHeldLeaksChunks tests CallTraceHashTable::clearTableOnly() but never instantiates or destroys a CallTraceStorage object. A mutation flipping the condition or removing the delete statement would not be caught by any test in this diff.

Suggestion: Add a test that instantiates CallTraceStorage, holds a RefCountGuard to force a drain timeout, then destroys the CallTraceStorage to verify the conditional-delete logic is correct. This would catch mutations of the condition or deletion of the delete statement.

ddprof-lib/src/main/cpp/callTraceStorage.cpp:229

[Sphinx Review — LOW] waitForRefCountToClear() now returns a safety-relevant bool, and the header says that on false the resource must not be freed. processTraces() is the only production caller in this file that still ignores the result. That is memory-safe today, because the later original_active->clear() drains again and leaks on timeout. But when the contract is broken, the ignored result has costs. (1) The thread holding lockAll() waits a second ~500ms on the same straggler. (2) DICTIONARY_DRAIN_TIMEOUTS is incremented twice and the warning is logged twice for one stall. (3) collect() runs over a table the code already knows a put() may still be writing. The PR description mentions the double wait and log, but the code keeps no record of the first result. So the 'must not be freed' rule for this table depends on clear() draining again, and nothing ties that drain to the decision already made at line 229.

Suggestion: Keep the result (const bool drained = ...) and use it. Either pass it to a clear variant that skips the redundant drain and leaks directly, or at least skip the second counter increment and log. If the current behavior is intentional, add a comment here saying the result is deliberately ignored because clear() -> clearTableOnly() re-drains and leaks on timeout. Without it, the ignored value reads like an oversight next to the destructor's checked calls.

ddprof-lib/src/main/cpp/callTraceHashTable.cpp:136

[Sphinx Review — LOW] The decrementCounters() comment (lines 136-137) says the _prev traversal is safe because waitForRefCountToClear(this) in clearTableOnly() "has already drained any in-flight put() operations". After this PR that premise only holds when the drain succeeds. clearTableOnly() now keeps going on a timeout: const bool drained = RefCountGuard::waitForRefCountToClear(this); decrementCounters();. It only checks drained at the very end, to decide whether to leak the chunks. So on the timeout path that the PR introduces, decrementCounters() walks _current_table/_prev while a put() may still hold a guard on this table and may be changing it, for example bumping sizes or expanding. Leaking the chunks keeps this memory-safe, but the comment now states an unconditional guarantee the code no longer gives. The counter decrement can also drift: a stalled put() can add to the trace counters after decrementCounters() has already subtracted them. The new clearTableOnly() comment documents the timeout path, but… (truncated)

Suggestion: Make the comment conditional. The traversal is race-free only when the drain succeeds. On a timeout it can race a stalled put(). It stays memory-safe because the chunks are leaked rather than freed, but counters may be slightly off. Alternatively, skip decrementCounters() when !drained, which would make the existing comment true again. Pick one and keep the comment consistent with it.

ddprof-lib/src/main/cpp/callTraceStorage.h:36

[Sphinx Review — LOW] The new class comment (and the matching bullet in doc/architecture/CallTraceStorage.md) says the destructor tolerates concurrent put(). That holds for processTraces(), but not for the destructor. put() loads _active_storage (callTraceStorage.cpp:120) before it takes the RefCountGuard on the table, then re-checks _active_storage. Suppose a put() is preempted between that load and the guard constructor. The destructor can then swap out the active table, find no guard on it, delete it and return, freeing the CallTraceStorage object. The resumed put() then constructs a guard on a deleted table and re-reads _active_storage from freed storage. The table-level drain cannot protect the containing object. The code is not reachable today (the PR notes Profiler::_instance is never deleted), but the new contract text overstates the guarantee, and a future caller could rely on it.

Suggestion: Limit the claim to processTraces(). State that the destructor requires put() to be quiesced (no thread can still be inside put() on this storage), and that its drain plus the leak on timeout are defense-in-depth for stragglers that already hold a guard. Apply the same wording to the CallTraceStorage.md bullet.

ddprof-lib/src/main/cpp/refCountGuard.h:122

[Sphinx Review — MEDIUM] The function now returns a value that matters for safety. The doc comment says that on false, ptr_to_delete must not be freed, but nothing in the type system enforces that. The PR itself names two existing callers that drop the result: the post-swap drain in CallTraceStorage::processTraces() and StringDictionary::rotate(). A future caller written in the old 'drain, then free' style compiles cleanly and brings back the use-after-free this PR is meant to prevent. The contract lives only in a comment.

Suggestion: Declare it [[nodiscard]] static bool waitForRefCountToClear(void* ptr_to_delete);. At the call sites where dropping the result is intentional (processTraces post-swap drain, StringDictionary::rotate), cast to (void) and add a one-line reason, so each discard is explicit and can be reviewed.