public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Dan Carpenter <error27@gmail.com>
To: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org
Subject: [smatch] sched_fair: check after dereference
Date: Mon, 20 Dec 2010 09:10:41 +0300	[thread overview]
Message-ID: <20101220061041.GA8512@bicker> (raw)

Hi Paul,

In linux-next e33078baa4 "sched: Fix update_cfs_load() synchronization"
introduced a dereference before the check for NULL.  I don't know the
code well enough to say if it's a bug or if the check can be removed.

kernel/sched_fair.c +728 update_cfs_load(6)
	warn: variable dereferenced before check 'cfs_rq'

   722  static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
   723  {
   724          u64 period = sysctl_sched_shares_window;
   725          u64 now, delta;
   726          unsigned long load = cfs_rq->load.weight;
                                     ^^^^^^^^^^^^^^^^^^^
   727
   728          if (!cfs_rq)
                     ^^^^^^
   729                  return;

Can you take a look?

regards,
dan carpenter


             reply	other threads:[~2010-12-20  6:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-20  6:10 Dan Carpenter [this message]
2010-12-24  9:17 ` [smatch] sched_fair: check after dereference Paul Turner

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=20101220061041.GA8512@bicker \
    --to=error27@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=pjt@google.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