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author | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-07-26 08:30:10 +0000 |
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committer | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-07-26 08:30:10 +0000 |
commit | 97538e813f8d41d7091aa6d1ffd15466117b26b1 (patch) | |
tree | fcebd0831122e048be356f6332a5a8bb00593617 /cont.c | |
parent | d3df0de693aefb942b7f38fa42854059d3cca14a (diff) | |
download | ruby-97538e813f8d41d7091aa6d1ffd15466117b26b1.tar.gz |
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.c | 10 |
1 files changed, 10 insertions, 0 deletions
@@ -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); } |