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

RDMA/cm: Fix leaking the multicast GID table reference

If the CM ID is destroyed while the CM event for multicast creating is
still queued the cancel_work_sync() will prevent the work from running
which also prevents destroying the ah_attr. This leaks a refcount and
triggers a WARN:

   GID entry ref leak for dev syz1 index 2 ref=573
   WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 release_gid_table drivers/infiniband/core/cache.c:806 [inline]
   WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 gid_table_release_one+0x284/0x3cc drivers/infiniband/core/cache.c:886

Destroy the ah_attr after canceling the work, it is safe to call this
twice.