Issue #21289 has been reported by dodecadaniel (Daniel Colson). ---------------------------------------- Bug #21289: Fix C level backtraces for USE_ELF https://bugs.ruby-lang.org/issues/21289 * Author: dodecadaniel (Daniel Colson) * Status: Open * ruby -v: ruby 3.4.3 (2025-04-14 revision d0b7e5b6a0) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- After upgrading GitHub to Ruby 3.4 we noticed that we stopped getting useful C level backtrace information in our crash reports. We traced it back to https://github.com/github/ruby/commit/7dd2afbe3a14d021e5554288517709f5778c3d.... Passing 0 instead of -1 makes sense for the Mach-O version of `fill_lines`, but there is a separate ELF version of `fill_lines` that still has special handling for -1: https://github.com/ruby/ruby/blob/58e3aa02240a9ec1b5fe6ce60d63828c2cf0c73a/a.... More details in the corresponding PR: https://github.com/ruby/ruby/pull/13195 -- https://bugs.ruby-lang.org/