Bug #8616
Process.daemon messes up threads
Description
=begin
Hi,
When I daemonize a process, it somehow messes up threads from the parent process. Here is a script to reproduce the problem:
r1, w1 = IO.pipe
r2, w2 = IO.pipe
t = Thread.new {
puts "start"
w1.write "x"
IO.select([r2])
puts "alive"
}
IO.select([r1])
Process.daemon true, true # comment this line out and everything works
puts Process.pid
w2.write "x"
t.join
puts "done"
If you run this program, there will be a ruby process in the background that never dies. If you comment out the "Process.daemon" line, the script finishes.
=end
Associated revisions
merge revision(s) 40534,41886,41903,41910: [Backport #8616]
process.c: rb_daemon should not raise * process.c (rb_daemon): should not raise exceptions, since
proc_daemon() will deal with errors.
* process.c (fork_daemon): kill the other threads all and abandon the
kept mutexes.
* process.c (fork_daemon): kill the other threads all and abandon the kept mutexes. * process.c (rb_daemon): daemon(3) is implemented with fork(2). Therefore it needs rb_thread_atfork(). (and revert r41903)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@44766 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
History
Updated by akr (Akira Tanaka) over 5 years ago
Updated by 2013/7/10 tenderlovemaking (Aaron Patterson) aaron@tenderlovemaking.com:
Bug #8616: Process.daemon messes up threads
https://bugs.ruby-lang.org/issues/8616
Process.daemon cannot preserve threads because
it uses fork and fork doesn't copy other threads.
Maybe, Process.daemon should raise an exception when
multi threads.
Updated by evanphx (Evan Phoenix) over 5 years ago
Updated by No, it shouldn't raise an exception. Process.daemon and fork both use
after_fork() in C. That function should iterate all the threads and mark
them as KILLED since they are all dead.
On Tue, Jul 9, 2013 at 6:14 PM, Tanaka Akira akr@fsij.org wrote:
2013/7/10 tenderlovemaking (Aaron Patterson) aaron@tenderlovemaking.com:
Bug #8616: Process.daemon messes up threads
https://bugs.ruby-lang.org/issues/8616Process.daemon cannot preserve threads because
it uses fork and fork doesn't copy other threads.Maybe, Process.daemon should raise an exception when
multi threads.
Updated by benweint (Ben Weintraub) over 5 years ago
Updated by I agree with Evan. The behavior he describes would be consistent with how threads are handled when a process forks via Process.fork in Ruby.
See this example for a demonstration: https://gist.github.com/benweint/6692546
Updated by benweint (Ben Weintraub) over 5 years ago
Actually, it looks like this is fixed in Ruby 2.1.0-preview1 (Thread#alive? returns false for background threads spawned before a call to Process.daemon), but still broken in 2.0.0-p247. Any chance of a backport?
Updated by benweint (Ben Weintraub) over 5 years ago
FWIW, it looks like the relevant change that fixed it for 2.1.0-preview1 was https://github.com/ruby/ruby/commit/300b7c80e
Updated by nagachika (Tomoyuki Chikanaga) over 5 years ago
Updated by - Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 1.9.3: UNKNOWN, 2.0.0: REQUIRED
I'll check r41910 to be backported later.
This ticket can be closed (for trunk)?
Updated by nagachika (Tomoyuki Chikanaga) over 5 years ago
- Status changed from Open to Closed
Updated by nagachika (Tomoyuki Chikanaga) over 5 years ago
- Backport changed from 1.9.3: UNKNOWN, 2.0.0: REQUIRED to 1.9.3: UNKNOWN, 2.0.0: DONE
Updated by usa (Usaku NAKAMURA) about 5 years ago
Updated by - Backport changed from 1.9.3: UNKNOWN, 2.0.0: DONE to 1.9.3: DONE, 2.0.0: DONE
backported into ruby_1_9_3 at r44766.
merge revision(s) 40534,41886,41903,41910: [Backport #8616]
proc_daemon() will deal with errors.
* process.c (fork_daemon): kill the other threads all and abandon the
kept mutexes.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43142 b2dd03c8-39d4-4d8f-98ff-823fe69b080e