diff options
author | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-12-22 01:41:18 +0000 |
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committer | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-12-22 01:41:18 +0000 |
commit | 0fd53f519fb37b1dfe37be9f53ebc7889f405114 (patch) | |
tree | 9243e5b507696ebe7bdc28bcaf3626f95d724248 /thread_sync.c | |
parent | 5072f03741087c869b2ded0c29349e9f3a361891 (diff) |
thread_sync.c (rb_mutex_t): eliminate fork_gen
The true bug fork_gen was hiding was rb_mutex_abandon_locking_mutex
failing to unconditionally clear the waitq of mutexes it was
waiting on. So we fix rb_mutex_abandon_locking_mutex, instead,
and eliminate rb_mutex_cleanup_keeping_mutexes.
This commit was tested heavily on a single-core Pentium-M which
was my most reliable reproducer of the "crash.rb" script from
[Bug #15383]
[Bug #14578] [Bug #15383]
Note: [Bug #15430] turned out to be an entirely different
problem: RLIMIT_NPROC limit was hit on the CI VMs.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66489 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'thread_sync.c')
-rw-r--r-- | thread_sync.c | 41 |
1 files changed, 1 insertions, 40 deletions
diff --git a/thread_sync.c b/thread_sync.c index dda92f196a..4c253f0e2a 100644 --- a/thread_sync.c +++ b/thread_sync.c @@ -45,17 +45,6 @@ typedef struct rb_mutex_struct { rb_thread_t *th; struct rb_mutex_struct *next_mutex; struct list_head waitq; /* protected by GVL */ - - /* - * FIXME: belt-and-suspenders redundancy. This field should NOT - * be necessary at all if: - * - rb_mutex_cleanup_keeping_mutexes - * - rb_mutex_abandon_keeping_mutexes - * - rb_mutex_abandon_locking_mutex - * are all correct, but I suspect one of them is buggy. - * [Bug #15383] [Bug #15430] - */ - rb_serial_t fork_gen; } rb_mutex_t; #if defined(HAVE_WORKING_FORK) @@ -132,17 +121,9 @@ 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); - /* FIXME: remove (see comment at rb_mutex_t definition) */ - 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); - } - return mutex; } @@ -428,8 +409,7 @@ rb_mutex_abandon_locking_mutex(rb_thread_t *th) if (th->locking_mutex) { rb_mutex_t *mutex = mutex_ptr(th->locking_mutex); - if (mutex->th == th) - rb_mutex_abandon_all(mutex); + list_head_init(&mutex->waitq); th->locking_mutex = Qfalse; } } @@ -447,25 +427,6 @@ rb_mutex_abandon_all(rb_mutex_t *mutexes) list_head_init(&mutex->waitq); } } - -/* - * All other threads are dead in the a new child process, so waitqs - * contain references to dead threads which we need to clean up - */ -static void -rb_mutex_cleanup_keeping_mutexes(const rb_thread_t *current_thread) -{ - rb_mutex_t *mutex = current_thread->keeping_mutexes; - rb_serial_t fork_gen = current_thread->vm->fork_gen; - - while (mutex) { - /* FIXME: remove (see comment at rb_mutex_t definition) */ - mutex->fork_gen = fork_gen; - - list_head_init(&mutex->waitq); - mutex = mutex->next_mutex; - } -} #endif static VALUE |