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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 34/36] avoid calling waitpid from children in DESTROY
Date: Thu, 31 Dec 2020 13:51:52 +0000	[thread overview]
Message-ID: <20201231135154.6070-35-e@80x24.org> (raw)
In-Reply-To: <20201231135154.6070-1-e@80x24.org>

Objects with DESTROY callbacks get propagated to children, so we
must be careful to not invoke waitpid from children on their
sibling processes.  Only parents (and their parents...) can reap
child processes.
---
 lib/PublicInbox/DS.pm         | 4 ++--
 lib/PublicInbox/Gcf2Client.pm | 8 ++++++--
 lib/PublicInbox/Git.pm        | 3 ++-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 01c9abd4..4f1558c7 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -624,10 +624,10 @@ sub dwaitpid ($;$$) {
 		if ($ret == $pid) {
 			if ($cb) {
 				eval { $cb->($arg, $pid) };
-				warn "E: dwaitpid($pid) !in_loop: $@" if $@;
+				carp "E: dwaitpid($pid) !in_loop: $@" if $@;
 			}
 		} else {
-			warn "waitpid($pid, 0) = $ret, \$!=$!, \$?=$?";
+			carp "waitpid($pid, 0) = $ret, \$!=$!, \$?=$?";
 		}
 	}
 }
diff --git a/lib/PublicInbox/Gcf2Client.pm b/lib/PublicInbox/Gcf2Client.pm
index 10820852..54957cf3 100644
--- a/lib/PublicInbox/Gcf2Client.pm
+++ b/lib/PublicInbox/Gcf2Client.pm
@@ -15,6 +15,7 @@ use PublicInbox::DS qw(dwaitpid);
 #	sock => writable pipe to Gcf2::loop
 #	in => pipe we read from
 #	pid => PID of Gcf2::loop process
+#	owner_pid => process which spawned {pid}
 sub new  {
 	my ($rdr) = @_;
 	my $self = bless {}, __PACKAGE__;
@@ -25,6 +26,7 @@ sub new  {
 	$rdr //= {};
 	$rdr->{0} = $out_r;
 	my $cmd = [$^X, qw[-MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop()]];
+	$self->{owner_pid} = $$;
 	@$self{qw(in pid)} = popen_rd($cmd, $env, $rdr);
 	fcntl($out_w, 1031, 4096) if $^O eq 'linux'; # 1031: F_SETPIPE_SZ
 	$out_w->autoflush(1);
@@ -69,8 +71,10 @@ sub DESTROY {
 	delete $self->{in};
 	# GitAsyncCat::event_step may reap us with WNOHANG, too
 	my $pid = delete $self->{pid} or return;
-	PublicInbox::DS->in_loop ? $self->close : delete($self->{sock});
-	dwaitpid $pid;
+	if ($$ == $self->{owner_pid}) {
+		PublicInbox::DS->in_loop ? $self->close : delete($self->{sock});
+		dwaitpid $pid;
+	}
 }
 
 # used by GitAsyncCat
diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index fdfe1269..47928c55 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -126,6 +126,7 @@ sub _bidi_pipe {
 	}
 	my ($in_r, $p) = popen_rd(\@cmd, undef, $redir);
 	$self->{$pid} = $p;
+	$self->{"$pid.owner"} = $$;
 	$out_w->autoflush(1);
 	if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ
 		fcntl($out_w, 1031, 4096);
@@ -327,7 +328,7 @@ sub _destroy {
 
 	# GitAsyncCat::event_step may delete {pid}
 	my $p = delete $self->{$pid} or return;
-	dwaitpid $p;
+	dwaitpid($p) if $$ == $self->{"$pid.owner"};
 }
 
 sub cat_async_abort ($) {

  parent reply	other threads:[~2020-12-31 13:51 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-31 13:51 [PATCH 00/36] another round of lei stuff Eric Wong
2020-12-31 13:51 ` [PATCH 01/36] import: respect init.defaultBranch Eric Wong
2020-12-31 13:51 ` [PATCH 02/36] lei_store: use per-machine refname as git HEAD Eric Wong
2020-12-31 13:51 ` [PATCH 03/36] revert "lei_store: use per-machine refname as git HEAD" Eric Wong
2020-12-31 13:51 ` [PATCH 04/36] lei_to_mail: initial implementation for writing mbox formats Eric Wong
2020-12-31 13:51 ` [PATCH 05/36] sharedkv: fork()-friendly key-value store Eric Wong
2020-12-31 13:51 ` [PATCH 06/36] sharedkv: split out index_values Eric Wong
2020-12-31 13:51 ` [PATCH 07/36] lei_to_mail: start atomic and compressed mbox writing Eric Wong
2020-12-31 13:51 ` [PATCH 08/36] mboxreader: new class for reading various mbox formats Eric Wong
2020-12-31 13:51 ` [PATCH 09/36] lei_to_mail: start --augment, dedupe, bz2 and xz Eric Wong
2020-12-31 13:51 ` [PATCH 10/36] lei: implement various deduplication strategies Eric Wong
2020-12-31 13:51 ` [PATCH 11/36] lei_to_mail: lazy-require LeiDedupe Eric Wong
2020-12-31 13:51 ` [PATCH 12/36] lei_to_mail: support for non-seekable outputs Eric Wong
2020-12-31 13:51 ` [PATCH 13/36] lei_to_mail: support Maildir, fix+test --augment Eric Wong
2020-12-31 13:51 ` [PATCH 14/36] ipc: generic IPC dispatch based on Storable Eric Wong
2020-12-31 13:51 ` [PATCH 15/36] ipc: support Sereal Eric Wong
2020-12-31 13:51 ` [PATCH 16/36] lei_store: add ->set_eml, ->add_eml can return smsg Eric Wong
2020-12-31 13:51 ` [PATCH 17/36] lei: rename "extinbox" => "external" Eric Wong
2020-12-31 13:51 ` [PATCH 18/36] mid: use defined-or with `push' for uniqueness check Eric Wong
2020-12-31 13:51 ` [PATCH 19/36] mid: hoist out mids_in sub Eric Wong
2020-12-31 13:51 ` [PATCH 20/36] lei_store: handle messages without Message-ID at all Eric Wong
2020-12-31 13:51 ` [PATCH 21/36] ipc: use shutdown(2), base atfork* callback Eric Wong
2020-12-31 13:51 ` [PATCH 22/36] lei_to_mail: unlink mboxes if not augmenting Eric Wong
2020-12-31 13:51 ` [PATCH 23/36] lei: add --mfolder as an --output alias Eric Wong
2020-12-31 13:51 ` [PATCH 24/36] spawn: move run_die here from PublicInbox::Import Eric Wong
2020-12-31 13:51 ` [PATCH 25/36] init: remove embedded UnlinkMe package Eric Wong
2020-12-31 13:51 ` [PATCH 26/36] t/run: avoid uninitialized var on incomplete test Eric Wong
2020-12-31 13:51 ` [PATCH 27/36] gcf2client: reap process on DESTROY Eric Wong
2020-12-31 13:51 ` [PATCH 28/36] lei_to_mail: open FIFOs O_WRONLY so we block Eric Wong
2020-12-31 13:51 ` [PATCH 29/36] searchidxshard: call DS->Reset at worker start Eric Wong
2020-12-31 13:51 ` [PATCH 30/36] t/ipc.t: test for references via `die' Eric Wong
2020-12-31 13:51 ` [PATCH 31/36] use PublicInbox::DS for dwaitpid Eric Wong
2020-12-31 13:51 ` [PATCH 32/36] syscall: SFD_NONBLOCK can be a constant, again Eric Wong
2020-12-31 13:51 ` [PATCH 33/36] lei: avoid Spawn package when starting daemon Eric Wong
2020-12-31 13:51 ` Eric Wong [this message]
2020-12-31 13:51 ` [PATCH 35/36] ds: clobber $in_loop first at reset Eric Wong
2020-12-31 13:51 ` [PATCH 36/36] on_destroy: support PID owner guard Eric Wong

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