From 63d9ab33fe419167382fc03be2c00413a78c05cb Mon Sep 17 00:00:00 2001 From: nagachika Date: Wed, 23 Jan 2019 14:14:25 +0000 Subject: [PATCH] merge revision(s) 62934,63210,63215,63309: [Backport #14634] thread_sync.c: avoid reaching across stacks of dead threads rb_ensure is insufficient cleanup for fork and we must reinitialize all waitqueues in the child process. Unfortunately this increases the footprint of ConditionVariable, Queue and SizedQueue by 8 bytes on 32-bit (16 bytes on 64-bit). [ruby-core:86316] [Bug #14634] variable.c: fix thread + fork errors in autoload This is fairly non-intrusive bugfix to prevent children from trying to reach into thread stacks of the parent. I will probably reuse this idea and redo r62934, too (same bug). * vm_core.h (typedef struct rb_vm_struct): add fork_gen counter * thread.c (rb_thread_atfork_internal): increment fork_gen * variable.c (struct autoload_data_i): store fork_gen * variable.c (check_autoload_data): remove (replaced with get_...) * variable.c (get_autoload_data): check fork_gen when retrieving * variable.c (check_autoload_required): use get_autoload_data * variable.c (rb_autoloading_value): ditto * variable.c (rb_autoload_p): ditto * variable.c (current_autoload_data): ditto * variable.c (autoload_reset): reset fork_gen, adjust indent * variable.c (rb_autoload_load): set fork_gen when setting state * test/ruby/test_autoload.rb (test_autoload_fork): new test [ruby-core:86410] [Bug #14634] thread_sync: redo r62934 to use fork_gen Instead of maintaining linked-lists to store all rb_queue/rb_szqueue/rb_condvar structs; store only a fork_gen serial number to simplify management of these items. This reduces initialization costs and avoids the up-front cost of resetting all Queue/SizedQueue/ConditionVariable objects at fork while saving 8 bytes per-structure on 64-bit. There are no savings on 32-bit. * thread.c (rb_thread_atfork_internal): remove rb_thread_sync_reset_all call * thread_sync.c (rb_thread_sync_reset_all): remove * thread_sync.c (queue_live): remove * thread_sync.c (queue_free): remove * thread_sync.c (struct rb_queue): s/live/fork_gen/ * thread_sync.c (queue_data_type): use default free * thread_sync.c (queue_alloc): remove list_add * thread_sync.c (queue_fork_check): new function * thread_sync.c (queue_ptr): call queue_fork_check * thread_sync.c (szqueue_free): remove * thread_sync.c (szqueue_data_type): use default free * thread_sync.c (szqueue_alloc): remove list_add * thread_sync.c (szqueue_ptr): check fork_gen via queue_fork_check * thread_sync.c (struct rb_condvar): s/live/fork_gen/ * thread_sync.c (condvar_free): remove * thread_sync.c (cv_data_type): use default free * thread_sync.c (condvar_ptr): check fork_gen * thread_sync.c (condvar_alloc): remove list_add [ruby-core:86316] [Bug #14634] thread_sync.c (condvar_ptr): reset fork_gen after forking Otherwise the condition variable waiter list will always be empty, which is wrong :x [Bug #14725] [Bug #14634] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@66912 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- test/ruby/test_autoload.rb | 26 +++++++++++++++++++++ test/thread/test_cv.rb | 19 +++++++++++++++ test/thread/test_queue.rb | 48 ++++++++++++++++++++++++++++++++++++++ thread.c | 2 ++ thread_sync.c | 43 +++++++++++++++++++++++++++++++--- variable.c | 32 ++++++++++++++++++------- version.h | 6 ++--- vm_core.h | 1 + 8 files changed, 162 insertions(+), 15 deletions(-) diff --git a/test/ruby/test_autoload.rb b/test/ruby/test_autoload.rb index 0220f3e27d..3095052a81 100644 --- a/test/ruby/test_autoload.rb +++ b/test/ruby/test_autoload.rb @@ -285,6 +285,32 @@ p Foo::Bar end end + def test_autoload_fork + EnvUtil.default_warning do + Tempfile.create(['autoload', '.rb']) {|file| + file.puts 'sleep 0.3; class AutoloadTest; end' + file.close + add_autoload(file.path) + begin + thrs = [] + 3.times do + thrs << Thread.new { AutoloadTest; nil } + thrs << Thread.new { fork { AutoloadTest } } + end + thrs.each(&:join) + thrs.each do |th| + pid = th.value or next + _, status = Process.waitpid2(pid) + assert_predicate status, :success? + end + ensure + remove_autoload_constant + assert_nil $!, '[ruby-core:86410] [Bug #14634]' + end + } + end + end if Process.respond_to?(:fork) + def add_autoload(path) (@autoload_paths ||= []) << path ::Object.class_eval {autoload(:AutoloadTest, path)} diff --git a/test/thread/test_cv.rb b/test/thread/test_cv.rb index 1e15d2e9ec..306cadd63b 100644 --- a/test/thread/test_cv.rb +++ b/test/thread/test_cv.rb @@ -217,4 +217,23 @@ INPUT Marshal.dump(condvar) end end + + def test_condvar_fork + mutex = Mutex.new + condvar = ConditionVariable.new + thrs = (1..10).map do + Thread.new { mutex.synchronize { condvar.wait(mutex) } } + end + thrs.each { 3.times { Thread.pass } } + pid = fork do + mutex.synchronize { condvar.broadcast } + exit!(0) + end + _, s = Process.waitpid2(pid) + assert_predicate s, :success?, 'no segfault [ruby-core:86316] [Bug #14634]' + until thrs.empty? + mutex.synchronize { condvar.broadcast } + thrs.delete_if { |t| t.join(0.01) } + end + end if Process.respond_to?(:fork) end diff --git a/test/thread/test_queue.rb b/test/thread/test_queue.rb index 4e6c9fa4c9..d69ecf92b2 100644 --- a/test/thread/test_queue.rb +++ b/test/thread/test_queue.rb @@ -565,4 +565,52 @@ class TestQueue < Test::Unit::TestCase puts 'exit' INPUT end + + def test_fork_while_queue_waiting + q = Queue.new + sq = SizedQueue.new(1) + thq = Thread.new { q.pop } + thsq = Thread.new { sq.pop } + Thread.pass until thq.stop? && thsq.stop? + + pid = fork do + exit!(1) if q.num_waiting != 0 + exit!(2) if sq.num_waiting != 0 + exit!(6) unless q.empty? + exit!(7) unless sq.empty? + q.push :child_q + sq.push :child_sq + exit!(3) if q.pop != :child_q + exit!(4) if sq.pop != :child_sq + exit!(0) + end + _, s = Process.waitpid2(pid) + assert_predicate s, :success?, 'no segfault [ruby-core:86316] [Bug #14634]' + + q.push :thq + sq.push :thsq + assert_equal :thq, thq.value + assert_equal :thsq, thsq.value + + sq.push(1) + th = Thread.new { q.pop; sq.pop } + thsq = Thread.new { sq.push(2) } + Thread.pass until th.stop? && thsq.stop? + pid = fork do + exit!(1) if q.num_waiting != 0 + exit!(2) if sq.num_waiting != 0 + exit!(3) unless q.empty? + exit!(4) if sq.empty? + exit!(5) if sq.pop != 1 + exit!(0) + end + _, s = Process.waitpid2(pid) + assert_predicate s, :success?, 'no segfault [ruby-core:86316] [Bug #14634]' + + assert_predicate thsq, :stop? + assert_equal 1, sq.pop + assert_same sq, thsq.value + q.push('restart th') + assert_equal 2, th.value + end if Process.respond_to?(:fork) end diff --git a/thread.c b/thread.c index 20e3deacdd..0cf48e38c6 100644 --- a/thread.c +++ b/thread.c @@ -4217,6 +4217,8 @@ rb_thread_atfork_internal(rb_thread_t *th, void (*atfork)(rb_thread_t *, const r } rb_vm_living_threads_init(vm); rb_vm_living_threads_insert(vm, th); + vm->fork_gen++; + vm->sleeper = 0; clear_coverage(); } diff --git a/thread_sync.c b/thread_sync.c index c7055578e6..396cceb2ce 100644 --- a/thread_sync.c +++ b/thread_sync.c @@ -4,6 +4,14 @@ static VALUE rb_cMutex, rb_cQueue, rb_cSizedQueue, rb_cConditionVariable; static VALUE rb_eClosedQueueError; +/* + * keep these globally so we can walk and reinitialize them at fork + * in the child process + */ +static LIST_HEAD(szqueue_list); +static LIST_HEAD(queue_list); +static LIST_HEAD(condvar_list); + /* sync_waiter is always on-stack */ struct sync_waiter { rb_thread_t *th; @@ -556,6 +564,7 @@ void rb_mutex_allow_trap(VALUE self, int val) #define queue_waitq(q) UNALIGNED_MEMBER_PTR(q, waitq) PACKED_STRUCT_UNALIGNED(struct rb_queue { struct list_head waitq; + rb_serial_t fork_gen; const VALUE que; int num_waiting; }); @@ -601,12 +610,29 @@ queue_alloc(VALUE klass) return obj; } +static int +queue_fork_check(struct rb_queue *q) +{ + rb_serial_t fork_gen = GET_VM()->fork_gen; + + if (q->fork_gen == fork_gen) { + return 0; + } + /* forked children can't reach into parent thread stacks */ + q->fork_gen = fork_gen; + list_head_init(queue_waitq(q)); + q->num_waiting = 0; + return 1; +} + static struct rb_queue * queue_ptr(VALUE obj) { struct rb_queue *q; TypedData_Get_Struct(obj, struct rb_queue, &queue_data_type, q); + queue_fork_check(q); + return q; } @@ -649,6 +675,11 @@ szqueue_ptr(VALUE obj) struct rb_szqueue *sq; TypedData_Get_Struct(obj, struct rb_szqueue, &szqueue_data_type, sq); + if (queue_fork_check(&sq->q)) { + list_head_init(szqueue_pushq(sq)); + sq->num_waiting_push = 0; + } + return sq; } @@ -885,7 +916,7 @@ queue_do_pop(VALUE self, struct rb_queue *q, int should_block) list_add_tail(&qw.as.q->waitq, &qw.w.node); qw.as.q->num_waiting++; - rb_ensure(queue_sleep, Qfalse, queue_sleep_done, (VALUE)&qw); + rb_ensure(queue_sleep, self, queue_sleep_done, (VALUE)&qw); } } @@ -1127,7 +1158,7 @@ rb_szqueue_push(int argc, VALUE *argv, VALUE self) list_add_tail(pushq, &qw.w.node); sq->num_waiting_push++; - rb_ensure(queue_sleep, Qfalse, szqueue_sleep_done, (VALUE)&qw); + rb_ensure(queue_sleep, self, szqueue_sleep_done, (VALUE)&qw); } } @@ -1228,9 +1259,9 @@ rb_szqueue_empty_p(VALUE self) /* ConditionalVariable */ -/* TODO: maybe this can be IMEMO */ struct rb_condvar { struct list_head waitq; + rb_serial_t fork_gen; }; /* @@ -1277,9 +1308,15 @@ static struct rb_condvar * condvar_ptr(VALUE self) { struct rb_condvar *cv; + rb_serial_t fork_gen = GET_VM()->fork_gen; TypedData_Get_Struct(self, struct rb_condvar, &cv_data_type, cv); + /* forked children can't reach into parent thread stacks */ + if (cv->fork_gen != fork_gen) { + list_head_init(&cv->waitq); + } + return cv; } diff --git a/variable.c b/variable.c index f700303d2f..bfb6fa2edd 100644 --- a/variable.c +++ b/variable.c @@ -20,6 +20,7 @@ #include "ccan/list/list.h" #include "id_table.h" #include "debug_counter.h" +#include "vm_core.h" struct rb_id_table *rb_global_tbl; static ID autoload, classpath, tmp_classpath, classid; @@ -1859,6 +1860,7 @@ struct autoload_data_i { rb_const_flag_t flag; VALUE value; struct autoload_state *state; /* points to on-stack struct */ + rb_serial_t fork_gen; }; static void @@ -1881,8 +1883,18 @@ static const rb_data_type_t autoload_data_i_type = { 0, 0, RUBY_TYPED_FREE_IMMEDIATELY }; -#define check_autoload_data(av) \ - (struct autoload_data_i *)rb_check_typeddata((av), &autoload_data_i_type) +static struct autoload_data_i * +get_autoload_data(VALUE av) +{ + struct autoload_data_i *ele = rb_check_typeddata(av, &autoload_data_i_type); + + /* do not reach across stack for ->state after forking: */ + if (ele && ele->state && ele->fork_gen != GET_VM()->fork_gen) { + ele->state = 0; + ele->fork_gen = 0; + } + return ele; +} RUBY_FUNC_EXPORTED void rb_autoload(VALUE mod, ID id, const char *file) @@ -1982,7 +1994,7 @@ check_autoload_required(VALUE mod, ID id, const char **loadingpath) const char *loading; int safe; - if (!(load = autoload_data(mod, id)) || !(ele = check_autoload_data(load))) { + if (!(load = autoload_data(mod, id)) || !(ele = get_autoload_data(load))) { return 0; } file = ele->feature; @@ -2020,7 +2032,7 @@ rb_autoloading_value(VALUE mod, ID id, VALUE* value, rb_const_flag_t *flag) VALUE load; struct autoload_data_i *ele; - if (!(load = autoload_data(mod, id)) || !(ele = check_autoload_data(load))) { + if (!(load = autoload_data(mod, id)) || !(ele = get_autoload_data(load))) { return 0; } if (ele->state && ele->state->thread == rb_thread_current()) { @@ -2087,8 +2099,9 @@ autoload_reset(VALUE arg) int need_wakeups = 0; if (state->ele->state == state) { - need_wakeups = 1; - state->ele->state = 0; + need_wakeups = 1; + state->ele->state = 0; + state->ele->fork_gen = 0; } /* At the last, move a value defined in autoload to constant table */ @@ -2170,7 +2183,7 @@ rb_autoload_load(VALUE mod, ID id) if (src && loading && strcmp(src, loading) == 0) return Qfalse; /* set ele->state for a marker of autoloading thread */ - if (!(ele = check_autoload_data(load))) { + if (!(ele = get_autoload_data(load))) { return Qfalse; } @@ -2180,6 +2193,7 @@ rb_autoload_load(VALUE mod, ID id) state.thread = rb_thread_current(); if (!ele->state) { ele->state = &state; + ele->fork_gen = GET_VM()->fork_gen; /* * autoload_reset will wake up any threads added to this @@ -2217,7 +2231,7 @@ rb_autoload_p(VALUE mod, ID id) } load = check_autoload_required(mod, id, 0); if (!load) return Qnil; - return (ele = check_autoload_data(load)) ? ele->feature : Qnil; + return (ele = get_autoload_data(load)) ? ele->feature : Qnil; } void @@ -2646,7 +2660,7 @@ current_autoload_data(VALUE mod, ID id) struct autoload_data_i *ele; VALUE load = autoload_data(mod, id); if (!load) return 0; - ele = check_autoload_data(load); + ele = get_autoload_data(load); if (!ele) return 0; /* for autoloading thread, keep the defined value to autoloading storage */ if (ele->state && (ele->state->thread == rb_thread_current())) { diff --git a/version.h b/version.h index 25eef3bdbd..65b18d62df 100644 --- a/version.h +++ b/version.h @@ -1,10 +1,10 @@ #define RUBY_VERSION "2.5.4" -#define RUBY_RELEASE_DATE "2019-01-20" -#define RUBY_PATCHLEVEL 137 +#define RUBY_RELEASE_DATE "2019-01-23" +#define RUBY_PATCHLEVEL 138 #define RUBY_RELEASE_YEAR 2019 #define RUBY_RELEASE_MONTH 1 -#define RUBY_RELEASE_DAY 20 +#define RUBY_RELEASE_DAY 23 #include "ruby/version.h" diff --git a/vm_core.h b/vm_core.h index cfe0042c25..a1de1ce327 100644 --- a/vm_core.h +++ b/vm_core.h @@ -507,6 +507,7 @@ typedef struct rb_vm_struct { struct rb_thread_struct *main_thread; struct rb_thread_struct *running_thread; + rb_serial_t fork_gen; struct list_head waiting_fds; /* <=> struct waiting_fd */ struct list_head living_threads; size_t living_thread_num;