From: Andrew Morton <akpm@linux-foundation.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Manfred Spraul <manfred@colorfullife.com>,
Davidlohr Bueso <davidlohr@hp.com>,
Rafael Aquini <aquini@redhat.com>
Subject: Re: [PATCH] ipc,sem block sem_lock on sma->lock during sma initialization
Date: Fri, 21 Nov 2014 12:09:30 -0800 [thread overview]
Message-ID: <20141121120930.3cd8d0f233f9670d689de672@linux-foundation.org> (raw)
In-Reply-To: <20141121145226.2ac598af@annuminas.surriel.com>
On Fri, 21 Nov 2014 14:52:26 -0500 Rik van Riel <riel@redhat.com> wrote:
> When manipulating just one semaphore with semop, sem_lock only takes that
> single semaphore's lock. This creates a problem during initialization of
> the semaphore array, when the data structures used by sem_lock have not
> been set up yet. The sma->lock is already held by newary, and we just
> have to make sure everything else waits on that lock during initialization.
>
> Luckily it is easy to make sem_lock wait on the sma->lock, by pretending
> there is a complex operation in progress while the sma is being initialized.
>
> The newary function already zeroes sma->complex_count before unlocking
> the sma->lock.
What are the runtime effects of the bug?
next prev parent reply other threads:[~2014-11-21 20:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-21 19:52 Rik van Riel
2014-11-21 20:07 ` Rafael Aquini
2014-11-21 20:09 ` Andrew Morton [this message]
2014-11-21 20:29 ` Rik van Riel
2014-11-21 20:42 ` Andrew Morton
2014-11-21 23:03 ` Rik van Riel
2014-11-22 0:56 ` Davidlohr Bueso
2014-11-22 3:40 ` Rik van Riel
2014-11-22 13:56 ` Manfred Spraul
2014-11-22 15:53 ` Rik van Riel
2014-11-22 19:14 ` Manfred Spraul
2014-11-22 20:14 ` Rik van Riel
2014-11-23 18:23 ` Manfred Spraul
2014-11-23 21:03 ` Rik van Riel
2014-11-23 21:36 ` Davidlohr Bueso
2014-11-24 10:41 ` Rafael Aquini
2014-11-24 20:49 ` Andrew Morton
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=20141121120930.3cd8d0f233f9670d689de672@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=aquini@redhat.com \
--cc=davidlohr@hp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=manfred@colorfullife.com \
--cc=riel@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
Powered by JetHome