[ruby-core:117882] [Ruby master Bug#20490] Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process
Issue #20490 has been reported by stanhu (Stan Hu). ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490 * Author: stanhu (Stan Hu) * Status: Open * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by stanhu (Stan Hu). I think this patch in the `ruby_3_2` branch fixes the problem: ```diff diff --git a/process.c b/process.c index 354e16fd26..bcf7f5aaf4 100644 --- a/process.c +++ b/process.c @@ -1291,6 +1299,9 @@ waitpid_wait(struct waitpid_state *w) if (w->ret == -1) w->errnum = errno; } else if (w->options & WNOHANG) { + if (w->pid < 0) { + need_sleep = TRUE; + } } else { need_sleep = TRUE; ``` ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-108298 * Author: stanhu (Stan Hu) * Status: Open * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by stanhu (Stan Hu). I've opened fixes here: * 3.2: https://github.com/ruby/ruby/pull/10771 * 3.1: https://github.com/ruby/ruby/pull/10772 ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-108299 * Author: stanhu (Stan Hu) * Status: Open * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by nagachika (Tomoyuki Chikanaga). Backport changed from 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN to 3.1: WONTFIX, 3.2: REQUIRED, 3.3: DONTNEED Thank you for your report. I will look the PRs. I will set the status of this ticket because of this is a backport ticket. And currently 3.1 branch is under the security maintenance phase, so I fill the Backport field for 3.1 with "WONTFIX". cc: @hsbt (as the new 3.1 branch maintainer). ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-108310 * Author: stanhu (Stan Hu) * Status: Open * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: WONTFIX, 3.2: REQUIRED, 3.3: DONTNEED ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by nagachika (Tomoyuki Chikanaga). Currently the backport PR for ruby_3_2 was made by @kjtsanaktsidis. https://github.com/ruby/ruby/pull/10787 But in my understanding, it was still in the works. ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-109176 * Author: stanhu (Stan Hu) * Status: Closed * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: WONTFIX, 3.2: REQUIRED, 3.3: DONTNEED ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by kjtsanaktsidis (KJ Tsanaktsidis). Apologies I missed this - I just rebased the branch, I think it should be OK for a stable backport to 3.2. ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-109373 * Author: stanhu (Stan Hu) * Status: Closed * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: WONTFIX, 3.2: REQUIRED, 3.3: DONTNEED ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
Issue #20490 has been updated by nagachika (Tomoyuki Chikanaga). Backport changed from 3.1: WONTFIX, 3.2: REQUIRED, 3.3: DONTNEED to 3.1: WONTFIX, 3.2: DONE, 3.3: DONTNEED Merged at https://github.com/ruby/ruby/commit/65fed1c3e439bc47bcf6ec884431a86cb9ebd1dc. Thank you! ---------------------------------------- Bug #20490: Process.waitpid2(-1, Process::WNOHANG) misbehaves on Ruby 3.1 & 3.2 with detached process https://bugs.ruby-lang.org/issues/20490#change-109448 * Author: stanhu (Stan Hu) * Status: Closed * ruby -v: ruby 3.2.4 (2024-04-23 revision af471c0e01) [x86_64-linux] * Backport: 3.1: WONTFIX, 3.2: DONE, 3.3: DONTNEED ---------------------------------------- This is a follow-up issue for a bug that I thought was fixed in https://bugs.ruby-lang.org/issues/19837 and duplicated in https://bugs.ruby-lang.org/issues/20181. The following script doesn't terminate quickly in Ruby 3.1.5 and 3.2.4, even with the patches to address https://bugs.ruby-lang.org/issues/19837. It works fine in Ruby 3.3. It appears that the `Process::WNOHANG` argument passed to `Process.wait2` causes this script to spin until the child process stops: ```ruby #!/bin/env ruby Process.spawn({}, "sh -c 'sleep 600'").tap do |pid| puts "detaching PID #{pid}" Process.detach(pid) end forked_pid = fork do loop { sleep 1 } end child_waiter = Thread.new do puts "Waiting for child process to die..." # The spawned process has to exit before this returns in Ruby 3.1 and 3.2 loop do pid, status = Process.wait2(-1, Process::WNOHANG) puts "Exited PID: #{pid}, status: #{status}" break if pid sleep 1 end end process_killer = Thread.new do puts "Killing #{forked_pid}" system("kill #{forked_pid}") end child_waiter.join process_killer.join ``` If I drop the `Process::WNOHANG` argument, it works fine. -- https://bugs.ruby-lang.org/
participants (3)
-
kjtsanaktsidis (KJ Tsanaktsidis) -
nagachika (Tomoyuki Chikanaga)
-
stanhu (Stan Hu)