From 2dd18df4a35a4b2dd0cf2dec7759898246fc6935 Mon Sep 17 00:00:00 2001 From: nagachika Date: Thu, 3 Jun 2021 20:46:53 +0900 Subject: merge revision(s) 86c262541ad07528842d76dab4b9b34bd888d5f4,7e14762159643b4415e094f9d2a90afaf7994588: [Backport #17935] Fix a race condition around mjit_recompile This fixes SEGVs like https://github.com/ruby/ruby/runs/2715166621?check_suite_focus=true. When mjit_recompile is called when mjit_compile is compiling the exact same iseq (and after it called mjit_capture_cc_entries), iseq->body->jit_unit is re-created and its cc_entries becomes NULL. Then, when it tries to lookup cc_entries through iseq->body->jit_unit, it fails. --- mjit.c | 21 +++++++++++++-------- mjit_worker.c | 4 ++++ 2 files changed, 17 insertions(+), 8 deletions(-) Do not doubly hold an MJIT lock This is a follow-up of 86c262541ad07528842d76dab4b9b34bd888d5f4. CRITICAL_SECTION_START/FINISH are not needed when it's called from an MJIT worker. Also, ZALLOC needs to be calloc because ZALLOC may trigger GC, which an MJIT worker must not do. --- mjit.c | 23 ++++++++++++++--------- mjit_worker.c | 4 ++-- 2 files changed, 16 insertions(+), 11 deletions(-) --- mjit_worker.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'mjit_worker.c') diff --git a/mjit_worker.c b/mjit_worker.c index ad36ec6151..e2db644c92 100644 --- a/mjit_worker.c +++ b/mjit_worker.c @@ -1402,6 +1402,8 @@ unload_units(void) } } +static void mjit_add_iseq_to_process(const rb_iseq_t *iseq, const struct rb_mjit_compile_info *compile_info, bool worker_p); + // The function implementing a worker. It is executed in a separate // thread by rb_thread_create_mjit_thread. It compiles precompiled header // and then compiles requested ISeqs. @@ -1451,6 +1453,8 @@ mjit_worker(void) unit->stale_p = false; remove_from_list(unit, &active_units); add_to_list(unit, &stale_units); + // Lazily put it to unit_queue as well to avoid race conditions on jit_unit with mjit_compile. + mjit_add_iseq_to_process(unit->iseq, &unit->iseq->body->jit_unit->compile_info, true); } } } -- cgit v1.2.3