Bug #20267
closed
Hashes that use ar_table aren't moved properly across ractors
Description
This crashes in debug build and gives weird results in non debug build, because the ar_table values aren't copied over to the new "embedded" hash during a move across ractors.
r = Ractor.new { hash = receive puts hash } obj = { "1" => 1, "2" => 2, "3" => 3, } puts obj r.send(obj, move: true) r.take Crash log:
/home/lukeg/workspace/ruby-build/miniruby(sigsegv+0x4d) [0x5641e67d105d] ../ruby/signal.c:926 /lib/x86_64-linux-gnu/libc.so.6(0x7fb4baa42520) [0x7fb4baa42520] /home/lukeg/workspace/ruby-build/miniruby(RB_BUILTIN_TYPE+0x0) [0x5641e6778db0] ../ruby/ractor.c:3128 /home/lukeg/workspace/ruby-build/miniruby(rbimpl_RB_TYPE_P_fastpath) ../ruby/include/ruby/internal/value_type.h:351 /home/lukeg/workspace/ruby-build/miniruby(RB_TYPE_P) ../ruby/include/ruby/internal/value_type.h:378 /home/lukeg/workspace/ruby-build/miniruby(RB_FL_ABLE) ../ruby/include/ruby/internal/fl_type.h:449 /home/lukeg/workspace/ruby-build/miniruby(RB_FL_TEST_RAW) ../ruby/include/ruby/internal/fl_type.h:471 /home/lukeg/workspace/ruby-build/miniruby(rb_ractor_shareable_p) ../ruby/include/ruby/ractor.h:256 /home/lukeg/workspace/ruby-build/miniruby(reset_belonging_enter) ../ruby/ractor.c:3121 
Updated by luke-gru (Luke Gruber) over 1 year ago
I created a patch here: https://github.com/ruby/ruby/pull/9983
Updated by hsbt (Hiroshi SHIBATA) about 1 year ago
- Status changed from Open to Assigned
- Assignee set to ko1 (Koichi Sasada)
Updated by byroot (Jean Boussier) 8 months ago
- Status changed from Assigned to Closed
Applied in changeset git|0350290262ea0fbc4e1807901797ee8a6970c2b9.
Ractor: Fix moving embedded objects
[Bug #20271]
[Bug #20267]
[Bug #20255]
rb_obj_alloc(RBASIC_CLASS(obj)) will always allocate from the basic
40B pool, so if obj is larger than 40B, we'll create a corrupted
object when we later copy the shape_id.
Instead we can use the same logic than ractor copy, which is
to use rb_obj_clone, and later ask the GC to free the original
object.
We then must turn it into a T_OBJECT, because otherwise
just changing its class to RactorMoved leaves a lot of
ways to keep using the object, e.g.:
a = [1, 2, 3] Ractor.new{}.send(a, move: true) [].concat(a) # Should raise, but wasn't. If it turns out that rb_obj_clone isn't performant enough
for some uses, we can always have carefully crafted specialized
paths for the types that would benefit from it.
Updated by byroot (Jean Boussier) 6 months ago
- Related to Bug #20165: Ractors moving a Struct breaks beyond the first 3 fields added