From: Arkadiusz Sienkiewicz <sienkiewiczarkadiusz@gmail.com>
To: dalias@libc.org
Cc: musl@lists.openwall.com
Subject: Re: aio_cancel segmentation fault for in progress write requests
Date: Fri, 7 Dec 2018 17:04:07 +0100 [thread overview]
Message-ID: <CAO=yjR1xdDHijaCAv0UpCKZCXBmyL_21SGBOQjQd+Z9dmjb2aw@mail.gmail.com> (raw)
In-Reply-To: <20181207154419.GD23599@brightrain.aerifal.cx>
[-- Attachment #1: Type: text/plain, Size: 3337 bytes --]
Ok, maybe stacktrace is misleading due to some problem in GDB. However,
that doesn't explain why I'm getting segmentation fault when I execute test
program without gdb. Also commenting aio_cancel line will "fix" seg fault,
so that function is most probable culprit.
pt., 7 gru 2018 o 16:44 Rich Felker <dalias@libc.org> napisał(a):
> On Fri, Dec 07, 2018 at 01:52:31PM +0100, Arkadiusz Sienkiewicz wrote:
> > Hi,
> >
> > I'm experiencing segmentation fault when I invoke aio_cancel on request
> > which is in EINPROGRESS state. This happens only with libc muls (used
> > version - 1.1.12-r8) and only on one (dual Intel Xeon Gold 6128) of few
> > computers I've tried it on - please let me know if you need more
> > information about that machine. Attached is very simple program
> > (aioWrite.cpp) that reproduces this problem.
> >
> > alpine-tmp-0:~$ ./aioWrite
> > Segmentation fault (core dumped)
> >
> > Bt from gdb shows problem is in aio_cancel.
>
> This is not correct:
>
> >
> > (gdb) r
> > Starting program: ~/aioWrite
> > [New LWP 70321]
> >
> > Program received signal ?, Unknown signal.
> > [Switching to LWP 70321]
>
> This just shows that the aio thread received the cancellation request.
> It's not a crash or a problem. However, gdb's reporting of it as
> "Unknown signal" and inability to pass it on correctly indicates that
> something is wrong with the gdb on your system. I've hit this issue a
> lot but it works on some systems and I don't recall what the
> cause/difference behind it is. We should work to figure that out and
> get an appropriate fix in distros that are affected.
>
>
> > #include <stdio.h>
> > #include <sys/types.h>
> > #include <unistd.h>
> > #include <sys/stat.h>
> > #include <fcntl.h>
> > #include <string.h>
> > #include <errno.h>
> > #include <stdlib.h>
> > #include <aio.h>
> >
> > #define TNAME "aio_write/1-1.c"
> >
> > int main() {
> > char tmpfname[256];
> > #define BUF_SIZE 512512
> > char buf[BUF_SIZE];
> > char check[BUF_SIZE+1];
> > int fd;
> > struct aiocb aiocb;
> > int err;
> > int ret;
> >
> > snprintf(tmpfname, sizeof(tmpfname), "pts_aio_write_1_1_%d", getpid());
> > unlink(tmpfname);
> > fd = open(tmpfname, O_CREAT | O_RDWR | O_EXCL, S_IRUSR | S_IWUSR);
> > if (fd == -1) {
> > printf(TNAME " Error at open(): %s\n", strerror(errno));
> > exit(1);
> > }
> >
> > unlink(tmpfname);
> >
> > memset(buf, 0xaa, BUF_SIZE);
> > memset(&aiocb, 0, sizeof(struct aiocb));
> > aiocb.aio_fildes = fd;
> > aiocb.aio_buf = buf;
> > aiocb.aio_nbytes = BUF_SIZE;
> >
> > if (aio_write(&aiocb) == -1) {
> > printf(TNAME " Error at aio_write(): %s\n", strerror(errno));
> > close(fd);
> > exit(2);
> > }
> >
> > int cancellationStatus = aio_cancel(fd, &aiocb);
> > printf (TNAME " cancelationStatus : %d\n", cancellationStatus);
> >
> > /* Wait until completion */
> > while (aio_error (&aiocb) == EINPROGRESS);
> >
> > close(fd);
> > printf ("Test PASSED\n");
> > return 0;
> > }
>
> I just tried this test and it works for me on 32-bit x86. I'll try
> some other systems and see if I can reproduce the issue. It could be a
> bug in the test but I didn't see anything obviously wrong with it.
>
> Rich
>
[-- Attachment #2: Type: text/html, Size: 4280 bytes --]
next prev parent reply other threads:[~2018-12-07 16:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-07 12:52 Arkadiusz Sienkiewicz
2018-12-07 15:44 ` Rich Felker
2018-12-07 16:04 ` Arkadiusz Sienkiewicz [this message]
2018-12-07 16:52 ` Orivej Desh
2018-12-07 16:52 ` Rich Felker
2018-12-07 17:31 ` A. Wilcox
2018-12-07 18:26 ` Rich Felker
2018-12-07 19:05 ` A. Wilcox
2018-12-07 20:07 ` Rich Felker
2018-12-07 19:13 ` A. Wilcox
2018-12-07 20:21 ` Rich Felker
2018-12-07 20:35 ` Markus Wichmann
2018-12-07 21:12 ` Rich Felker
2018-12-07 22:51 ` A. Wilcox
2018-12-07 23:50 ` Rich Felker
2018-12-07 20:06 ` Florian Weimer
2018-12-07 20:14 ` Rich Felker
2018-12-08 16:18 ` Florian Weimer
2018-12-10 9:05 ` Arkadiusz Sienkiewicz
2018-12-12 0:36 ` Rich Felker
2018-12-17 14:21 ` Arkadiusz Sienkiewicz
2018-12-17 17:29 ` Rich Felker
Reply instructions:
You may reply publicly 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
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAO=yjR1xdDHijaCAv0UpCKZCXBmyL_21SGBOQjQd+Z9dmjb2aw@mail.gmail.com' \
--to=sienkiewiczarkadiusz@gmail.com \
--cc=dalias@libc.org \
--cc=musl@lists.openwall.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).