In the Linux kernel, the following vulnerability has been resolved:

ax25: Fix reference count leak issues of ax25_dev

The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference
count leak issue of the object "ax25_dev".

Memory leak issue in ax25_addr_ax25dev():

The reference count of the object "ax25_dev" can be increased multiple
times in ax25_addr_ax25dev(). This will cause a memory leak.

Memory leak issues in ax25_dev_device_down():

The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and
then increase the reference count when ax25_dev is added to ax25_dev_list.
As a result, the reference count of ax25_dev is 2. But when the device is
shutting down. The ax25_dev_device_down() drops the reference count once
or twice depending on if we goto unlock_put or not, which will cause
memory leak.

As for the issue of ax25_addr_ax25dev(), it is impossible for one pointer
to be on a list twice. So add a break in ax25_addr_ax25dev(). As for the
issue of ax25_dev_device_down(), increase the reference count of ax25_dev
once in ax25_dev_device_up() and decrease the reference count of ax25_dev
after it is removed from the ax25_dev_list.

kernel.org https://git.kernel.org/stable/c/1ea02699c7557eeb35ccff2bd822de1b3e09d868 [No types assigned]

kernel.org https://git.kernel.org/stable/c/38eb01edfdaa1562fa00429be2e33f45383b1b3a [No types assigned]

kernel.org https://git.kernel.org/stable/c/81d8240b0a243b3ddd8fa8aa172f1acc2f7cc8f3 [No types assigned]

kernel.org https://git.kernel.org/stable/c/ae467750a3765dd1092eb29f58247950a2f9b60c [No types assigned]

kernel.org https://git.kernel.org/stable/c/b505e0319852b08a3a716b64620168eab21f4ced [No types assigned]