All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jakub Kicinski <kuba@kernel.org>
To: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
	davem@davemloft.net, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: sched: gred: potential dereference of null pointer
Date: Wed, 8 Dec 2021 18:36:08 -0800	[thread overview]
Message-ID: <20211208183608.27852c15@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20211209021346.2004600-1-jiasheng@iscas.ac.cn>

On Thu,  9 Dec 2021 10:13:46 +0800 Jiasheng Jiang wrote:
> The return value of kzalloc() needs to be checked.
> To avoid use of null pointer in gred_change_vq() in case
> of the failure of alloc.
> 
> Fixes: 869aa41044b0 ("sch_gred: prefer GFP_KERNEL allocations")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

I don't see how. Please explain in more detail. gred_change_vq() gets 
a pointer to a pointer and checks if its values is NULL.

> diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
> index f4132dc25ac0..c0d355281baf 100644
> --- a/net/sched/sch_gred.c
> +++ b/net/sched/sch_gred.c
> @@ -697,6 +697,8 @@ static int gred_change(struct Qdisc *sch, struct nlattr *opt,
>  	}
>  
>  	prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
> +	if (!prealloc)
> +		return -ENOMEM;
>  	sch_tree_lock(sch);
>  
>  	err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc,


      reply	other threads:[~2021-12-09  2:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-09  2:13 [PATCH] net: sched: gred: potential dereference of null pointer Jiasheng Jiang
2021-12-09  2:36 ` Jakub Kicinski [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=20211208183608.27852c15@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com \
    --to=kuba@kernel.org \
    --cc=davem@davemloft.net \
    --cc=jhs@mojatatu.com \
    --cc=jiasheng@iscas.ac.cn \
    --cc=jiri@resnulli.us \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=xiyou.wangcong@gmail.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.