diff options
| author | Stan Lo <[email protected]> | 2023-01-16 20:42:51 +0000 |
|---|---|---|
| committer | Peter Zhu <[email protected]> | 2023-01-17 08:01:19 -0500 |
| commit | df6b72b8ff7af16a56fa48f3b4abb1d8850f4d1c (patch) | |
| tree | 67fd7da4f7a26e5e1af3153eba8581c5dc49c400 | |
| parent | 9399352a43253e2905d76d21774fb0301069197b (diff) | |
Avoid checking interrupt when loading iseq
The interrupt check will unintentionally release the VM lock when loading an iseq.
And this will cause issues with the `debug` gem's
[`ObjectSpace.each_iseq` method](https://github.com/ruby/debug/blob/0fcfc28acae33ec1c08068fb7c33703cfa681fa7/ext/debug/iseq_collector.c#L61-L67),
which wraps iseqs with a wrapper and exposes their internal states when they're actually not ready to be used.
And when that happens, errors like this would occur and kill the `debug` gem's thread:
```
DEBUGGER: ReaderThreadError: uninitialized InstructionSequence
┃ DEBUGGER: Disconnected.
┃ ["/opt/rubies/ruby-3.2.0/lib/ruby/gems/3.2.0/gems/debug-1.7.1/lib/debug/breakpoint.rb:247:in `absolute_path'",
┃ "/opt/rubies/ruby-3.2.0/lib/ruby/gems/3.2.0/gems/debug-1.7.1/lib/debug/breakpoint.rb:247:in `block in iterate_iseq'",
┃ "/opt/rubies/ruby-3.2.0/lib/ruby/gems/3.2.0/gems/debug-1.7.1/lib/debug/breakpoint.rb:246:in `each_iseq'",
...
```
A way to reproduce the issue is to satisfy these conditions at the same time:
1. `debug` gem calling `ObjectSpace.each_iseq` (e.g. [activating a `LineBreakpoint`](https://github.com/ruby/debug/blob/0fcfc28acae33ec1c08068fb7c33703cfa681fa7/lib/debug/breakpoint.rb#L246)).
2. A large amount of iseq being loaded from another thread (possibly through the `bootsnap` gem).
3. 1 and 2 iterating through the same iseq(s) at the same time.
Because this issue requires external dependencies and a rather complicated timing setup to reproduce, I wasn't able to write a test case for it.
But here's some pseudo code to help reproduce it:
```rb
require "debug/session"
Thread.new do
100.times do
ObjectSpace.each_iseq do |iseq|
iseq.absolute_path
end
end
end
sleep 0.1
load_a_bunch_of_iseq
possibly_through_bootsnap
```
[Bug #19348]
Co-authored-by: Peter Zhu <[email protected]>
| -rw-r--r-- | compile.c | 2 | ||||
| -rw-r--r-- | vm_core.h | 1 | ||||
| -rw-r--r-- | vm_insnhelper.c | 11 |
3 files changed, 13 insertions, 1 deletions
@@ -12311,7 +12311,7 @@ ibf_load_iseq_each(struct ibf_load *load, rb_iseq_t *iseq, ibf_offset_t offset) verify_call_cache(iseq); RB_GC_GUARD(dummy_frame); - rb_vm_pop_frame(ec); + rb_vm_pop_frame_no_int(ec); } struct ibf_dump_iseq_list_arg @@ -1747,6 +1747,7 @@ const VALUE *rb_binding_add_dynavars(VALUE bindval, rb_binding_t *bind, int dync void rb_vm_inc_const_missing_count(void); VALUE rb_vm_call_kw(rb_execution_context_t *ec, VALUE recv, VALUE id, int argc, const VALUE *argv, const rb_callable_method_entry_t *me, int kw_splat); +void rb_vm_pop_frame_no_int(rb_execution_context_t *ec); MJIT_STATIC void rb_vm_pop_frame(rb_execution_context_t *ec); void rb_thread_start_timer_thread(void); diff --git a/vm_insnhelper.c b/vm_insnhelper.c index 29753f1800..0ce7fb6cc7 100644 --- a/vm_insnhelper.c +++ b/vm_insnhelper.c @@ -405,6 +405,17 @@ vm_push_frame(rb_execution_context_t *ec, vm_push_frame_debug_counter_inc(ec, cfp, type); } +void +rb_vm_pop_frame_no_int(rb_execution_context_t *ec) +{ + rb_control_frame_t *cfp = ec->cfp; + + if (VM_CHECK_MODE >= 4) rb_gc_verify_internal_consistency(); + if (VMDEBUG == 2) SDR(); + + ec->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp); +} + /* return TRUE if the frame is finished */ static inline int vm_pop_frame(rb_execution_context_t *ec, rb_control_frame_t *cfp, const VALUE *ep) |