From 818f1c65ab6534acdbe539616843cfec3ac794fa Mon Sep 17 00:00:00 2001 From: normal Date: Wed, 5 Dec 2018 18:58:45 +0000 Subject: thread_sync.c (mutex_ptr): handle mutexes held by parent threads in children Mutexes may be held by threads which only exist in the parent process, so their waitqueues may be populated with references to other dead threads. We must reset them at fork. I am a moron for introducing this bug :< [ruby-core:90312] [Bug #15383] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66230 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- thread_sync.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'thread_sync.c') diff --git a/thread_sync.c b/thread_sync.c index b79db1fee3..e478a96b88 100644 --- a/thread_sync.c +++ b/thread_sync.c @@ -45,6 +45,7 @@ typedef struct rb_mutex_struct { rb_thread_t *th; struct rb_mutex_struct *next_mutex; struct list_head waitq; /* protected by GVL */ + rb_serial_t fork_gen; } rb_mutex_t; #if defined(HAVE_WORKING_FORK) @@ -121,8 +122,18 @@ static rb_mutex_t * mutex_ptr(VALUE obj) { rb_mutex_t *mutex; + rb_serial_t fork_gen = GET_VM()->fork_gen; TypedData_Get_Struct(obj, rb_mutex_t, &mutex_data_type, mutex); + + if (mutex->fork_gen != fork_gen) { + /* forked children can't reach into parent thread stacks */ + mutex->fork_gen = fork_gen; + list_head_init(&mutex->waitq); + mutex->next_mutex = 0; + mutex->th = 0; + } + return mutex; } -- cgit v1.2.3