Bug #8770: [PATCH] process.c: avoid EINTR from Process.spawn

• Status: Assigned
• Priority: Normal
• Assignee: nobu (Nobuyoshi Nakada)
• Target version: -
• ruby -v: 44687,44706,44727
• Backport: 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: DONE

[normalperson (Eric Wong)]

(send_child_error): retry write on EINTR
(recv_child_error): retry read on EINTR

I've been getting occasional Errno::EINTR from Process.spawn with
just the prog name in the error message. This is probably the cause
of it, as I haven't been able to get a consistent reproduction of
the Errno::EINTR.

I've been hitting this on 2.0.0-p247, so it probably needs backport.

[nobu (Nobuyoshi Nakada)]

patch please

[normalperson (Eric Wong)]

• File 0001-process.c-avoid-EINTR-from-Process.spawn.patch 0001-process.c-avoid-EINTR-from-Process.spawn.patch added

Oops, attached

[naruse (Yui NARUSE)]

• Status changed from Open to Assigned
• Assignee set to nobu (Nobuyoshi Nakada)

[normalperson (Eric Wong)]

It looks like r44687 implements a partial fix for this, but my
proposed patch covers more cases and is more complete.

* process.c (recv_child_error): Fix deadlock in rb_fork_internal when a
  signal is sent to the parent process while Ruby is forking in IO.popen.

 Patch by Scott Francis. Closes GH-513.

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed
• Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED

Oops, I missed to include the reference in r44706.

[normalperson (Eric Wong)]

[e-mail] wrote:

Oops, I missed to include the reference in r44706.

No worries. Interesting, now I notice test_process now fails under
heavy load with this patch...

This should fix things: http://bogomips.org/ruby.git/patch?id=81b6f37afe34

git://80x24.org/ruby.git test_process-avoid-teardown

[nobu (Nobuyoshi Nakada)]

Is it an issue of the test code?

http://c5664.rubyci.org/~chkbuild/ruby-trunk/log/20140125T233302Z.log.html.gz

[normalperson (Eric Wong)]

[e-mail] wrote:

Is it an issue of the test code?

http://c5664.rubyci.org/~chkbuild/ruby-trunk/log/20140125T233302Z.log.html.gz

Odd, I did not get this:

10) Error:
TestProcess#test_deadlock_by_signal_at_forking:
Errno::EINTR: Interrupted system call - /home/chkbuild/build/20140125T233302Z/ruby/ruby
/home/chkbuild/build/20140125T233302Z/ruby/test/ruby/test_process.rb:1875:in popen'
/home/chkbuild/build/20140125T233302Z/ruby/test/ruby/test_process.rb:1875:inblock in test_deadlock_by_signal_at_forking'
/home/chkbuild/build/20140125T233302Z/ruby/test/ruby/test_process.rb:1873:in times'
/home/chkbuild/build/20140125T233302Z/ruby/test/ruby/test_process.rb:1873:intest_deadlock_by_signal_at_forking'

Instead, I got this (with TESTS=-j32):

/home/ew/ruby/test/ruby/test_process.rb:15:in waitall': SIGTERM (SignalException)
/home/ew/ruby/test/ruby/test_process.rb:15:inteardown'
/home/ew/ruby/lib/minitest/unit.rb:1280:in `block in run'

I don't think I was able to reproduce it on a single-threaded test-all.

[akr (Akira Tanaka)]

I think the Errno::EINTR error occur inTestProcess#test_deadlock_by_signal_at_forking because
r44706 doesn't contain the last hunk in 0001-process.c-avoid-EINTR-from-Process.spawn.patch.

I committed the hunk at r44727.

[normalperson (Eric Wong)]

[e-mail] wrote:

I think the Errno::EINTR error occur inTestProcess#test_deadlock_by_signal_at_forking because
r44706 doesn't contain the last hunk in 0001-process.c-avoid-EINTR-from-Process.spawn.patch.

I committed the hunk at r44727.

Good catch, things look good, thanks!

[tmm1 (Aman Gupta)]

• Tracker changed from Bug to Backport
• Target version deleted (2.1.0)
• Project changed from Ruby trunk to Backport21
• Category deleted (core)
• Status changed from Closed to Assigned

[naruse (Yui NARUSE)]

• Tracker changed from Backport to Bug
• Project changed from Backport21 to Ruby trunk
• ruby -v set to -
• Backport set to 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN

I wrote https://bugs.ruby-lang.org/projects/ruby/wiki/HowToRequestBackport

[naruse (Yui NARUSE)]

• ruby -v changed from - to 44687,44706,44727
• Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED

COMMITS: 44687,44706,44727

[naruse (Yui NARUSE)]

• Backport changed from 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: DONE

r45061 on ruby_2_1