Issue #19917 has been reported by toy (Ivan Kuchin). ---------------------------------------- Bug #19917: Segmentation fault or lost objects when using Ractor.select with moved exceptions https://bugs.ruby-lang.org/issues/19917 * Author: toy (Ivan Kuchin) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- I stumbled upon loss of messages with exceptions or even Segmentation fault during transfer of exception from Ractor when moving the exception. In versions 3.0 and 3.1 I saw only loss of messages, in 3.2 also Segmentation fault. Loss of messages happens only when using `Ractor.select` (not `Ractor#take`), but segmentation fault happens also using `Ractor#take`. ```ruby 100.times do ractor_count = 10 ractors = Array.new(ractor_count) do |i| Ractor.new do begin raise 'foo' rescue => e # It is not possible to move exception without duplicating, but also # without it showing bactrace errors in 3.0 and is empty in 3.1+ e = Marshal.load(Marshal.dump(e)) Ractor.yield e, move: true end 'message got lost' end end ractor_count.times do ractor, result = Ractor.select(*ractors) p result ractors.delete(ractor) end end ``` In 3.0 and 3.1 will contain mix of `#<RuntimeError: foo>` and `"message got lost"`, in 3.2 may contain both and cause Segmentation fault. Excerpt of output (full output attached) from container running ruby:3.2 (`ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]`): ``` … #<RuntimeError: RuntimeError> "message got lost" #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> #<RuntimeError: RuntimeError> <internal:marshal>:34: [BUG] Segmentation fault at 0x0000000000000000 ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux] -- Control frame information ----------------------------------------------- c:0004 p:0006 s:0019 e:000018 METHOD <internal:marshal>:34 c:0003 p:0022 s:0011 e:000010 RESCUE (irb):11 c:0002 p:0007 s:0007 e:000006 BLOCK (irb):6 [FINISH] c:0001 p:---- s:0003 e:000002 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- (irb):6:in `block (3 levels) in <top (required)>' (irb):11:in `rescue in block (3 levels) in <top (required)>' <internal:marshal>:34:in `load' -- Machine register context ------------------------------------------------ RIP: 0x00007fabc1d64490 RBP: 0x0000000000000000 RSP: 0x00007fabbc71b0c0 RAX: 0x0000000000000003 RBX: 0x00007fabbcebee88 RCX: 0x000000000000015f RDX: 0x0000556127db90f0 RDI: 0x000000000000015f RSI: 0x00007fabc2068628 R8: 0x0000000000000001 R9: 0x0000000000000020 R10: 0x00005561285633d0 R11: 0x0000000000000001 R12: 0x0000556127dbb710 R13: 0x00007fabc0601be0 R14: 0x0000000000000018 R15: 0x0000000000000000 EFL: 0x0000000000010206 … ``` ---Files-------------------------------- segmentation-fault.txt (27.8 KB) -- https://bugs.ruby-lang.org/