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From: Dan Carpenter <dan.carpenter@linaro.org>
To: Lars Kellogg-Stedman <lars@oddbit.com>
Cc: Duoming Zhou <duoming@zju.edu.cn>,
	linux-hams@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, pabeni@redhat.com, kuba@kernel.org,
	edumazet@google.com, davem@davemloft.net, jreuter@yaina.de
Subject: Re: [PATCH net] ax25: Fix refcount leak issues of ax25_dev
Date: Sat, 4 May 2024 15:16:55 +0300	[thread overview]
Message-ID: <1e14f4f1-29dd-4fe5-8010-de7df0866e93@moroto.mountain> (raw)
In-Reply-To: <ekgwuycs3hioz6vve57e6z7igovpls6s644rvdxpxqqr7v7is6@u5lqegkuwcex>

On Fri, May 03, 2024 at 07:40:32PM -0400, Lars Kellogg-Stedman wrote:
> On Fri, May 03, 2024 at 11:36:37PM +0300, Dan Carpenter wrote:
> > Could you test this diff?
> 
> With that diff applied, there is no kernel panic, but I see the same
> refcount errors that I saw before the latest series of patches from
> Duoming:

Wait, which panic is this?  The NULL dereference introduce by the
"ax25_dev" vs "res" typo?

> 
>   refcount_t: decrement hit 0; leaking memory.
>   refcount_t: underflow; use-after-free.

Hm...  Is there a missing netdev_hold() in ax25_bind() on the
"User already set interface with SO_BINDTODEVICE" path?  That would
fit with the commit 9fd75b66b8f6 ("ax25: Fix refcount leaks caused by
ax25_cb_del()") which introduced the bug.

I'm not really sure I understand how netdev_hold() works.

(My patch here is correct, but apparently that's not the bug).

regards,
dan carpenter

  reply	other threads:[~2024-05-04 12:17 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-01  6:02 [PATCH net] ax25: Fix refcount leak issues of ax25_dev Duoming Zhou
2024-05-01 17:33 ` Markus Elfring
2024-05-01 17:43 ` Dan Carpenter
2024-05-02  4:35   ` duoming
2024-05-02  7:56     ` Dan Carpenter
2024-05-02  9:30       ` Paolo Abeni
2024-05-02  1:29 ` Lars Kellogg-Stedman
2024-05-03 20:36   ` Dan Carpenter
2024-05-03 23:40     ` Lars Kellogg-Stedman
2024-05-04 12:16       ` Dan Carpenter [this message]
2024-05-04 22:16         ` Lars Kellogg-Stedman
2024-05-07  3:18           ` Lars Kellogg-Stedman
2024-05-07  8:08             ` Dan Carpenter
2024-05-07  9:04               ` duoming
2024-05-09  1:40               ` duoming
2024-05-23 12:30               ` Lars Kellogg-Stedman
2024-05-07  6:38     ` Dan Carpenter
2024-05-15  9:52   ` duoming
2024-05-04 11:04 ` Dan Carpenter

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