From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by sourceware.org (Postfix) with ESMTPS id D157C3858D1E for ; Mon, 18 Mar 2024 11:08:55 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D157C3858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=ispras.ru Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=ispras.ru ARC-Filter: OpenARC Filter v1.0.0 sourceware.org D157C3858D1E Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=83.149.199.84 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1710760138; cv=none; b=UQUl0a2/HRos690ZMS75IRbLWBhXvD7vBU6p1mgEgSTFaR5wHzquA5cJTVkXYkjeT2upJA73IYTvQxOm539hMTyriTIyHQAvYUEbQKXmMl7otlGrUIZsLiIwn4Scny1sYG68P4gOvs1mQo9XR09HxGKKD+E8a1O4z+8HHv4LAWE= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1710760138; c=relaxed/simple; bh=Ix6jXxokYMgh19TaU8cyWAXW3nseTeOwhegFthr3uvw=; h=DKIM-Signature:MIME-Version:Date:From:To:Subject:Message-ID; b=mPNundsvXm/2cFKAnGY/bC+DwQMlQx3JN8Nvpsak8OtbzUkCyBzqydxLdsQE5wo8DZI+tanu/Hg9xRZDkTkGSRsNXqnq/DKK7rQcmRCA6hLy9m1UZ1QKK+lS7hrdZKMN3Hq15cFaZidcgKEIY2H/m3GHIcHlPbBywJhvDuAiZS4= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from mail.ispras.ru (unknown [83.149.199.84]) by mail.ispras.ru (Postfix) with ESMTPSA id D98A94076749; Mon, 18 Mar 2024 11:08:53 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru D98A94076749 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1710760133; bh=WdMxiowSmGpw2+gZC3xxfy/MWEFfggbzJKxUjDajoV4=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=GPoaJcfFXHuTzlphaWrWF5fXFQcwGjSiG/UEceBqDIPnvLoOTBVc9jvKV2j+LxWHz HgkfF0uIOvZdgkJpbHuNoTmhH2YSKPl91d5GhIUVtZKjdP+pV7msDTcJqDPOb6BGcR DjHN3LNGFPxgQsFQYIbXhAaxm2Dd6JPZscaJZn68= MIME-Version: 1.0 Date: Mon, 18 Mar 2024 14:08:53 +0300 From: Alexey Izbyshev To: takashi.yano@nifty.ne.jp Cc: dimitry@unified-streaming.com, cygwin@cygwin.com Subject: Re: Bogus exit code 127 from a child process In-Reply-To: <20240318135826.e4176868074e074eb3138cb5@nifty.ne.jp> User-Agent: Roundcube Webmail/1.4.13 Message-ID: <6cdb036ad7bbc1227a470dcd8f105544@ispras.ru> X-Sender: izbyshev@ispras.ru Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 2024-03-18 07:58, Takashi Yano wrote: > On Mon, 18 Mar 2024 12:09:06 +0900 > Takashi Yano wrote: >> On Sun, 17 Mar 2024 14:10:55 +0100 >> Dimitry Andric wrote: >> > On 17 Mar 2024, at 13:50, Dimitry Andric wrote: >> > > >> > > On 17 Mar 2024, at 13:35, Takashi Yano via Cygwin wrote: >> > > ... >> > >> >> > >> I also test your test case: >> > >> while bash -c 'true & true & wait -n || { echo 1: $?; exit 1; } && wait -n || { echo 2: $?; exit 1; }'; do echo $((i++)); done >> > >> in Linux (Debian 12.5), and the issue reproduced! >> > > >> > > Yeah, same here with bash 5.1.16(1)-release on Ubuntu 22.04. It errors out with 127 after ~50-200 loops. >> > >> > Having built bash master (bash-5.2-27-gf3b6bd19) here, it consistently gives 127 in this area: >> > >> > https://git.savannah.gnu.org/cgit/bash.git/tree/builtins/wait.def#n227 >> > >> > 211 #if defined (JOB_CONTROL) >> > 212 if (nflag) >> > 213 { >> > 214 if (list) >> > 215 { >> > 216 opt = set_waitlist (list); >> > 217 if (opt == 0) >> > 218 WAIT_RETURN (127); >> > 219 wflags |= JWAIT_WAITING; >> > 220 } >> > 221 >> > 222 status = wait_for_any_job (wflags, &pstat); >> > 223 if (vname && status >= 0) >> > 224 builtin_bind_var_to_int (vname, pstat.pid, bindflags); >> > 225 >> > 226 if (status < 0) >> > => 227 status = 127; >> > 228 if (list) >> > 229 unset_waitlist (); >> > 230 WAIT_RETURN (status); >> > 231 } >> > 232 #endif >> > >> > So for some reason, wait_for_any_job() returns a negative value in this particular situation. >> >> Line 218 looks also suspicious. > > Probably, this is not a bug. man bash says: > If the -n option is supplied, wait waits for a single > job from > the list of ids or, if no ids are supplied, any job, to > complete > and returns its exit status. If none of the supplied > arguments > is a child of the shell, or if no arguments are supplied > and the > shell has no unwaited‐for children, the exit status is > 127. > > If the background process exited before calling 'wait -n', it returns > 127. > This is very different from wait() system call, which is necessary for > any background joubs, otherwise zombie remains. > > In the shell, it is not necessary to call wait command for background > jobs, > therefore exit status of the background job which already exited is not > held > anymore. > > So, actual bug is in the test case. I missed the subthread starting from your bash version request due to not being CCed, so replying via the mail archive link. I'm sorry for wasting your time with the bad test case. I should have tested on Linux first myself. Thank you, Takashi and Dimitry. The original problem with make that I was reproducing doesn't involve "wait -n" or any bash background jobs though, so this puts me back to the point before (I thought) I eliminated make. I'll try my older reproducers with new Cygwin versions, and will probably look at make source code (since it's starting to look like it might be a bug in make, not in Cygwin) before posting further. Thanks, Alexey