xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: Wei Liu <wei.liu2@citrix.com>
To: Sergei Lebedev <sergei.a.lebedev@gmail.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Wei Liu <wei.liu2@citrix.com>,
	David Vrabel <david.vrabel@citrix.com>,
	xen-devel@lists.xen.org
Subject: Re: Xen 4.4, xenstored and WATCH requests
Date: Fri, 26 Feb 2016 12:42:14 +0000	[thread overview]
Message-ID: <20160226124214.GE644@citrix.com> (raw)
In-Reply-To: <C427D120-6CB5-4A0B-AFB3-6C3860E664D2@gmail.com>

(CC'ing Linux maintainers)

OK. Thanks for all the information.

This seems to be a bug in Linux xenbus driver.

Relevant code snippet in
drivers/xen/xenbus/xenbus_dev_frontend.c:xenbus_write_watch()


  /* Success.  Synthesize a reply to say all is OK. */
  {
          struct {
                  struct xsd_sockmsg hdr;
                  char body[3];
          } __packed reply = {
                  {
                          .type = msg_type,
                          .len = sizeof(reply.body)
                  },
                  "OK"
          };
  
          mutex_lock(&u->reply_mutex);
          rc = queue_reply(&u->read_buffers, &reply, sizeof(reply));
          wake_up(&u->read_waitq);
          mutex_unlock(&u->reply_mutex);
  }

The synthesised reply doesn't echo the req_id back to user.

Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

      reply	other threads:[~2016-02-26 12:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-25 12:54 Xen 4.4, xenstored and WATCH requests Sergei Lebedev
2016-02-26 11:26 ` Wei Liu
2016-02-26 12:07   ` Wei Liu
2016-02-26 12:10   ` Sergei Lebedev
2016-02-26 12:42     ` Wei Liu [this message]

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=20160226124214.GE644@citrix.com \
    --to=wei.liu2@citrix.com \
    --cc=boris.ostrovsky@oracle.com \
    --cc=david.vrabel@citrix.com \
    --cc=sergei.a.lebedev@gmail.com \
    --cc=xen-devel@lists.xen.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
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).