[Bug #21127] Thread deadlock does not display backtraces (#12721)

Previously, Ruby displayed backtraces for each thread on deadlock. However, it has not been shown since Ruby 3.0.
It should display the backtrace for debugging.

Co-authored-by: Jeremy Evans <code@jeremyevans.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/thread.c b/thread.c
index c4e304231d..359671ba9e 100644
--- a/thread.c
+++ b/thread.c
@@ -5588,7 +5588,7 @@ debug_deadlock_check(rb_ractor_t *r, VALUE msg)
             }
         }
         rb_str_catf(msg, "\n   ");
-        rb_str_concat(msg, rb_ary_join(rb_ec_backtrace_str_ary(th->ec, 0, 0), sep));
+        rb_str_concat(msg, rb_ary_join(rb_ec_backtrace_str_ary(th->ec, RUBY_BACKTRACE_START, RUBY_ALL_BACKTRACE_LINES), sep));
         rb_str_catf(msg, "\n");
     }
 }