Linux-Next Archive on lore.kernel.org
 help / color / Atom feed
From: Vincent Guittot <vincent.guittot@linaro.org>
To: coverity-bot <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	linux-next@vger.kernel.org
Subject: Re: Coverity: find_idlest_group(): Null pointer dereferences
Date: Tue, 29 Oct 2019 09:07:09 +0100
Message-ID: <CAKfTPtDji9SC6OZ8Aurjn5mxR_bmMnoZN82h=RdC9v-0wTzHSQ@mail.gmail.com> (raw)
In-Reply-To: <201910281603.4378C08@keescook>

On Tue, 29 Oct 2019 at 00:03, coverity-bot <keescook@chromium.org> wrote:
>
> Hello!
>
> This is an experimental automated report about issues detected by Coverity
> from a scan of next-20191025 as part of the linux-next weekly scan project:
> https://scan.coverity.com/projects/linux-next-weekly-scan
>
> You're getting this email because you were associated with the identified
> lines of code (noted below) that were touched by recent commits:
>
> 57abff067a08 ("sched/fair: Rework find_idlest_group()")
>
> Coverity reported the following:
>
> *** CID 1487371:  Null pointer dereferences  (FORWARD_NULL)
> /kernel/sched/fair.c: 8319 in find_idlest_group()
> 8313            case group_asym_packing:
> 8314                    /* Those type are not used in the slow wakeup path */
> 8315                    return NULL;
> 8316
> 8317            case group_misfit_task:
> 8318                    /* Select group with the highest max capacity */
> vvv     CID 1487371:  Null pointer dereferences  (FORWARD_NULL)
> vvv     Dereferencing null pointer "local".
> 8319                    if (local->sgc->max_capacity >= idlest->sgc->max_capacity)

Local can't be NULL and will be set in the loop above because this_cpu
belongs to one of the groups of its sched_domain

> 8320                            return NULL;
> 8321                    break;
> 8322
> 8323            case group_has_spare:
> 8324                    if (sd->flags & SD_NUMA) {
>
> If this is a false positive, please let us know so we can mark it as
> such, or teach the Coverity rules to be smarter. If not, please make
> sure fixes get into linux-next. :) For patches fixing this, please
> include:
>
> Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
> Addresses-Coverity-ID: 1487371 ("Null pointer dereferences")
> Fixes: 57abff067a08 ("sched/fair: Rework find_idlest_group()")
>
>
> Thanks for your attention!
>
> --
> Coverity-bot

      reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28 23:03 coverity-bot
2019-10-29  8:07 ` Vincent Guittot [this message]

Reply instructions:

You may reply publically 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='CAKfTPtDji9SC6OZ8Aurjn5mxR_bmMnoZN82h=RdC9v-0wTzHSQ@mail.gmail.com' \
    --to=vincent.guittot@linaro.org \
    --cc=gustavo@embeddedor.com \
    --cc=keescook@chromium.org \
    --cc=linux-next@vger.kernel.org \
    --cc=mingo@kernel.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

Linux-Next Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-next/0 linux-next/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-next linux-next/ https://lore.kernel.org/linux-next \
		linux-next@vger.kernel.org
	public-inbox-index linux-next

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-next


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git