All of lore.kernel.org
 help / color / mirror / Atom feed
From: Roland Dreier <rdreier@cisco.com>
To: Nathan Lynch <ntl@pobox.com>
Cc: linux-kernel@vger.kernel.org, openib-general@openib.org,
	openfabrics-ewg@openib.org, Christoph Hellwig <hch@infradead.org>,
	linuxppc-dev@ozlabs.org, raisch@de.ibm.com,
	Hoang-Nam Nguyen <hnguyen@linux.vnet.ibm.com>
Subject: Re: [PATCH/RFC 2.6.21 3/5] ehca: completion queue: remove use of do_mmap()
Date: Thu, 11 Jan 2007 11:56:18 -0800	[thread overview]
Message-ID: <adaodp5ibh9.fsf@cisco.com> (raw)
In-Reply-To: <20070111194054.GA11770@localdomain> (Nathan Lynch's message of "Thu, 11 Jan 2007 13:40:54 -0600")

 > >  	spin_lock_irqsave(&ehca_cq_idr_lock, flags);
 > >  	while (my_cq->nr_callbacks)
 > >  		yield();

 > Isn't that code outright buggy?  Calling into the scheduler with a
 > spinlock held and local interrupts disabled...

Yes, absolutely -- if nr_callbacks is ever nonzero then this will
obviously crash instantly.

 - R.

WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier@cisco.com>
To: Nathan Lynch <ntl@pobox.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Hoang-Nam Nguyen <hnguyen@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	openfabrics-ewg@openib.org, openib-general@openib.org,
	raisch@de.ibm.com
Subject: Re: [PATCH/RFC 2.6.21 3/5] ehca: completion queue: remove use of do_mmap()
Date: Thu, 11 Jan 2007 11:56:18 -0800	[thread overview]
Message-ID: <adaodp5ibh9.fsf@cisco.com> (raw)
In-Reply-To: <20070111194054.GA11770@localdomain> (Nathan Lynch's message of "Thu, 11 Jan 2007 13:40:54 -0600")

 > >  	spin_lock_irqsave(&ehca_cq_idr_lock, flags);
 > >  	while (my_cq->nr_callbacks)
 > >  		yield();

 > Isn't that code outright buggy?  Calling into the scheduler with a
 > spinlock held and local interrupts disabled...

Yes, absolutely -- if nr_callbacks is ever nonzero then this will
obviously crash instantly.

 - R.

  parent reply	other threads:[~2007-01-11 19:56 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-11 19:08 [PATCH/RFC 2.6.21 3/5] ehca: completion queue: remove use of do_mmap() Hoang-Nam Nguyen
2007-01-11 19:20 ` Christoph Hellwig
2007-01-11 19:20   ` Christoph Hellwig
2007-01-11 19:40   ` Nathan Lynch
2007-01-11 19:43     ` Christoph Hellwig
2007-01-11 19:43       ` Christoph Hellwig
2007-01-11 19:56     ` Roland Dreier [this message]
2007-01-11 19:56       ` Roland Dreier
2007-01-12 15:23       ` Hoang-Nam Nguyen
2007-01-12 15:23         ` Hoang-Nam Nguyen
2007-01-12 15:36   ` Hoang-Nam Nguyen
2007-01-12 15:36     ` Hoang-Nam Nguyen

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=adaodp5ibh9.fsf@cisco.com \
    --to=rdreier@cisco.com \
    --cc=hch@infradead.org \
    --cc=hnguyen@linux.vnet.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=ntl@pobox.com \
    --cc=openfabrics-ewg@openib.org \
    --cc=openib-general@openib.org \
    --cc=raisch@de.ibm.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.