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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-07-26 08:30:10 (GMT)
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-07-26 08:30:10 (GMT)
commit97538e813f8d41d7091aa6d1ffd15466117b26b1 (patch)
treefcebd0831122e048be356f6332a5a8bb00593617 /cont.c
parentd3df0de693aefb942b7f38fa42854059d3cca14a (diff)
cont.c (ec_switch): prevent delayed/missed trap interrupt race
timer-thread may set trap interrupt with rb_threadptr_check_signal at any time independent of GVL. This means timer-thread may set the trap interrupt flag on the previous execution context; causing the flag to be unnoticed until a future ec switch (or lost completely if the ec is done). Note: I avoid relying on th->interrupt_lock here and use atomics because we won't be able to rely on it for proposed lazy timer-thread [Misc #14937]. This regression affects Ruby 2.5 as it was introduced by moving interrupt_flag to `ec' which is an unstable pointer. Ruby <= 2.4 was unaffected because vm->main_thread->interrupt_flag never changed. [ruby-core:88119] [Bug #14939] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64062 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'cont.c')
-rw-r--r--cont.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/cont.c b/cont.c
index 082b47d..1f82a79 100644
--- a/cont.c
+++ b/cont.c
@@ -262,7 +262,17 @@ static inline void
ec_switch(rb_thread_t *th, rb_fiber_t *fib)
{
rb_execution_context_t *ec = &fib->cont.saved_ec;
+
ruby_current_execution_context_ptr = th->ec = ec;
+
+ /*
+ * timer-thread may set trap interrupt on previous th->ec at any time;
+ * ensure we do not delay (or lose) the trap interrupt handling.
+ */
+ if (th->vm->main_thread == th && rb_signal_buff_size() > 0) {
+ RUBY_VM_SET_TRAP_INTERRUPT(ec);
+ }
+
VM_ASSERT(ec->fiber_ptr->cont.self == 0 || ec->vm_stack != NULL);
}