From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM12-MW2-obe.outbound.protection.outlook.com (mail-mw2nam12on2112.outbound.protection.outlook.com [40.107.244.112]) by sourceware.org (Postfix) with ESMTPS id 61164385E006 for ; Thu, 26 Mar 2020 23:19:19 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 61164385E006 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=MduhOBMlhLR2iIfFRuYttDtYLmz267Q3aY7Vd/LHkCArsET9A1hLiJ7moYDt1h2EyZr0HvNEgRjQsLylNWpZ7suoyLV4b4yBcIMiErnxVb81k28/pHvUJ9Cr9lhJ1dwrTzE0OgwW0op3pDFzNp1X8B9g8ByXODn0T7+6wOMfVKeLtm7lnjILvR4s1jTeE1YHsgjJ5llczsQjaPBf5bUxTD9ef9SiJjX4l8db3wiZTgqg4n86ahpLgePc/+6oJDspzHZJ030xDwz3ZSIzt4VQcSMrBNDKZKgVKLzQQxLORF0CmYwB64KrozWg2zhpexpZgrYixUR8fSG5e3hdzOV53w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=1HadIEfbMIDuDxDeOGbud+66uy5HM9WOxHEw+jXCsHM=; 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charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit On 3/26/2020 6:39 PM, Ken Brown via Cygwin wrote: > On 3/26/2020 6:01 PM, sten.kristian.ivarsson@gmail.com wrote: >> The ENIXIO occurs when parallel child-processes simultaneously using >> O_NONBLOCK opening the descriptor. > > This is consistent with my guess that the error is generated by > fhandler_fifo::wait.  I have a feeling that read_ready should have been created > as a manual-reset event, and that more care is needed to make sure it's set when > it should be. > >> I could provide a code-snippet >> to reproduce it if wanted ? > > Yes, please! That might not be necessary. If you're able to build the git repo master branch, please try the attached patch. Ken --------------CE98C37F39D315F56A5799FF Content-Type: text/plain; charset=UTF-8; name="0001-Cygwin-FIFO-make-read_ready-a-manual-reset-event.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-Cygwin-FIFO-make-read_ready-a-manual-reset-event.patch" >From 279591d91a13616957964256e02344a627b6f558 Mon Sep 17 00:00:00 2001 From: Ken Brown Date: Thu, 26 Mar 2020 19:02:16 -0400 Subject: [PATCH] Cygwin: FIFO: make read_ready a manual-reset event If a FIFO is open for reading and an attempt is made to open it for writing with O_NONBLOCK, read_ready must be set in order for open to succeed. When read_ready was an auto-reset event, there was a brief period when read_ready was not set set after a writer opened. If a second writer attempted to open the FIFO with O_NONBLOCK during this period, the attempt would fail. Addresses: https://sourceware.org/pipermail/cygwin/2020-March/244201.html --- winsup/cygwin/fhandler_fifo.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc index 19cd0e507..c05161099 100644 --- a/winsup/cygwin/fhandler_fifo.cc +++ b/winsup/cygwin/fhandler_fifo.cc @@ -516,7 +516,7 @@ fhandler_fifo::open (int flags, mode_t) char npbuf[MAX_PATH]; __small_sprintf (npbuf, "r-event.%08x.%016X", get_dev (), get_ino ()); - if (!(read_ready = CreateEvent (sa_buf, false, false, npbuf))) + if (!(read_ready = CreateEvent (sa_buf, true, false, npbuf))) { debug_printf ("CreateEvent for %s failed, %E", npbuf); res = error_set_errno; -- 2.21.0 --------------CE98C37F39D315F56A5799FF--