Re: [PATCH v0] mctp: fix netdev reference bug

Hi Matt,

Oops, sorry for the false alarm, I found this on mainline kernel and I should checkout net-next before sending the patch.

Regards

Hi Lin Ma,

On Thu, 2022-03-24 at 10:39 +0800, Lin Ma wrote:

quoted

In extended addressing mode, function mctp_local_output() fetch netdev
through dev_get_by_index_rcu, which won't increase netdev's reference
counter. Hence, the reference may underflow when mctp_local_output calls
dev_put(), results in possible use after free.

This patch adds dev_hold() to fix the reference bug.

This was already fixed in net-next to increment the refcount in
__mctp_dev_get() and use mctp_dev_put().

dc121c008491 ("mctp: make __mctp_dev_get() take a refcount hold")
e297db3eadd7 ("mctp: Fix incorrect netdev unref for extended addr")

Thanks,
Matt