From: Eric Dumazet <eric.dumazet@gmail.com>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: sched: sch_teql: fix null-pointer dereference
Date: Thu, 8 Apr 2021 17:26:00 +0200 [thread overview]
Message-ID: <0c385039-3780-b5d0-ba36-c1c51da9bc08@gmail.com> (raw)
In-Reply-To: <20210408151431.9512-1-ptikhomirov@virtuozzo.com>
On 4/8/21 5:14 PM, Pavel Tikhomirov wrote:
> Reproduce:
>
> modprobe sch_teql
> tc qdisc add dev teql0 root teql0
>
> This leads to (for instance in Centos 7 VM) OOPS:
>
>
>
> Null pointer dereference happens on master->slaves dereference in
> teql_destroy() as master is null-pointer.
>
> When qdisc_create() calls teql_qdisc_init() it imediately fails after
> check "if (m->dev == dev)" because both devices are teql0, and it does
> not set qdisc_priv(sch)->m leaving it zero on error path, then
> qdisc_create() imediately calls teql_destroy() which does not expect
> zero master pointer and we get OOPS.
>
> Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
> ---
This makes sense, thanks !
Reviewed-by: Eric Dumazet <edumazet@google.com>
I would think bug origin is
Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
Can you confirm you have this backported to 3.10.0-1062.7.1.el7.x86_64 ?
next prev parent reply other threads:[~2021-04-08 15:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 15:14 [PATCH] net: sched: sch_teql: fix null-pointer dereference Pavel Tikhomirov
2021-04-08 15:26 ` Eric Dumazet [this message]
2021-04-08 15:51 ` Pavel Tikhomirov
2021-04-08 21:20 ` patchwork-bot+netdevbpf
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