In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix potential use after free in counter_release() When acce

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

RDMA/core: Fix potential use after free in counter_release()

When accessing a counter via the netlink path the only synchronization
mechanism for the said counter is rdma_restrack_get().
Currently, rdma_restrack_del() is invoked at the end of
counter_release(), which is too late, since by that point
vendor-specific resources associated with the counter might already be
freed. This can leave a short window where the counter remains
accessible through restrack, leading to a potential use-after-free.

Fix this by moving the rdma_restrack_del() call to be before the
freeing of the vendor-specific resources, ensuring that the counter is
removed from restrack before its internal resources are released.
This guarantees that no new users hold references to a counter that is
in the process of destruction.