user/dev discussion of public-inbox itself
 help / color / Atom feed
From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 4/4] DS: epoll: fix misordered EPOLL_CTL_DEL call
Date: Wed,  8 May 2019 19:18:56 +0000
Message-ID: <20190508191856.20485-5-e@80x24.org> (raw)
In-Reply-To: <20190508191856.20485-1-e@80x24.org>

Any operations on an fd after POSIX::close() are invalid, so
epoll_ctl will fail.  Worse off, in a multi-threaded Perl, the
fd may be reused by another thread and EPOLL_CTL_DEL can hit the
wrong file description as a result.

cf. https://rt.cpan.org/Ticket/Display.html?id=129487
---
 lib/PublicInbox/DS.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index c03bd5d..779215c 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -333,8 +333,8 @@ sub EpollEventLoop {
                 } else {
                     my $fd = $ev->[0];
                     warn "epoll() returned fd $fd w/ state $state for which we have no mapping.  removing.\n";
-                    POSIX::close($fd);
                     epoll_ctl($Epoll, EPOLL_CTL_DEL, $fd, 0);
+                    POSIX::close($fd);
                 }
                 next;
             }
-- 
EW


      parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-05  0:52 [PATCH 0/4] bundle Danga::Socket and Sys::Syscall Eric Wong
2019-05-05  0:52 ` [PATCH 1/4] " Eric Wong
2019-05-05  4:56   ` [PATCH 5/4] DS: workaround IO::Kqueue EINTR (mis-)handling Eric Wong
2019-05-08  9:07   ` [PATCH 6/4] DS: handle EINTR in IO::Poll path, too Eric Wong
2019-05-05  0:52 ` [PATCH 2/4] listener: use EPOLLEXCLUSIVE for listen sockets Eric Wong
2019-05-05  0:52 ` [PATCH 3/4] DS: remove unused fields and functions Eric Wong
2019-05-05  0:52 ` [PATCH 4/4] DS: drop profiling support Eric Wong
2019-05-08 19:18 ` [PATCH 0/4] Danga::Socket bundling cleanups Eric Wong
2019-05-08 19:18   ` [PATCH 1/4] build: do not manify DS and Syscall pods Eric Wong
2019-05-08 19:18   ` [PATCH 2/4] syscall: drop readahead wrapper Eric Wong
2019-05-08 19:18   ` [PATCH 3/4] DS: drop unused "_undef" sub Eric Wong
2019-05-08 19:18   ` Eric Wong [this message]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://public-inbox.org/README

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190508191856.20485-5-e@80x24.org \
    --to=e@80x24.org \
    --cc=meta@public-inbox.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

user/dev discussion of public-inbox itself

Archives are clonable:
	git clone --mirror http://public-inbox.org/meta
	git clone --mirror http://czquwvybam4bgbro.onion/meta
	git clone --mirror http://hjrcffqmbrq6wope.onion/meta
	git clone --mirror http://ou63pmih66umazou.onion/meta

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.mail.public-inbox.meta
	nntp://ou63pmih66umazou.onion/inbox.comp.mail.public-inbox.meta
	nntp://czquwvybam4bgbro.onion/inbox.comp.mail.public-inbox.meta
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.mail.public-inbox.meta
	nntp://news.gmane.org/gmane.mail.public-inbox.general

 note: .onion URLs require Tor: https://www.torproject.org/

AGPL code for this site: git clone https://public-inbox.org/ public-inbox