qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: Eric Blake <eblake@redhat.com>
To: Jeff Cody <jcody@redhat.com>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, famz@redhat.com, qemu-block@nongnu.org,
	mreitz@redhat.com, stefanha@redhat.com, pbonzini@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 for-2.11 2/4] coroutine: abort if we try to schedule or enter a pending coroutine
Date: Tue, 21 Nov 2017 06:20:34 -0600	[thread overview]
Message-ID: <6343710b-dcad-4f0e-d669-d3b554606062@redhat.com> (raw)
In-Reply-To: <1f0fd95c2096688add2c7b3cfcd7016756ef19fb.1511230683.git.jcody@redhat.com>

[-- Attachment #1: Type: text/plain, Size: 1126 bytes --]

On 11/20/2017 08:23 PM, Jeff Cody wrote:
> The previous patch fixed a race condition, in which there were
> coroutines being executing doubly, or after coroutine deletion.
> 
> We can detect common scenarios when this happens, and print an error
> message and abort before we corrupt memory / data, or segfault.
> 
> This patch will abort if an attempt to enter a coroutine is made while
> it is currently pending execution, either in a specific AioContext bh,
> or pending execution via a timer.  It will also abort if a coroutine
> is scheduled, before a prior scheduled run has occured.

s/occured/occurred/

> 
> We cannot rely on the existing co->caller check for recursive re-entry
> to catch this, as the coroutine may run and exit with
> COROUTINE_TERMINATE before the scheduled coroutine executes.
> 
> (This is the scenario that was occuring and fixed in the previous

s/occuring/occurring/

> patch).
> 
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 619 bytes --]

  parent reply	other threads:[~2017-11-21 12:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-21  2:23 [Qemu-devel] [PATCH v2 for-2.11 0/4] Fix segfault in blockjob race condition Jeff Cody
2017-11-21  2:23 ` [Qemu-devel] [PATCH v2 for-2.11 1/4] blockjob: do not allow coroutine double entry or entry-after-completion Jeff Cody
2017-11-21 10:49   ` Stefan Hajnoczi
2017-11-21 13:12     ` Paolo Bonzini
2017-11-21 13:26       ` Jeff Cody
2017-11-21  2:23 ` [Qemu-devel] [PATCH v2 for-2.11 2/4] coroutine: abort if we try to schedule or enter a pending coroutine Jeff Cody
2017-11-21 10:59   ` Stefan Hajnoczi
2017-11-21 13:11     ` Paolo Bonzini
2017-11-21 12:20   ` Eric Blake [this message]
2017-11-21 13:47   ` Kevin Wolf
2017-11-21 15:11     ` Paolo Bonzini
2017-11-21  2:23 ` [Qemu-devel] [PATCH v2 for-2.11 3/4] qemu-iotests: add option in common.qemu for mismatch only Jeff Cody
2017-11-21  2:23 ` [Qemu-devel] [PATCH v2 for-2.11 4/4] qemu-iotest: add test for blockjob coroutine race condition Jeff Cody

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=6343710b-dcad-4f0e-d669-d3b554606062@redhat.com \
    --to=eblake@redhat.com \
    --cc=famz@redhat.com \
    --cc=jcody@redhat.com \
    --cc=kwolf@redhat.com \
    --cc=mreitz@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-block@nongnu.org \
    --cc=qemu-devel@nongnu.org \
    --cc=stefanha@redhat.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.
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).