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

firmware: arm_scmi: Avoid IDR updates while cleaning channels

scmi_cleanup_channels() walks the TX/RX channel IDRs with
idr_for_each() to free transport resources and destroy the dedicated
transport devices before calling idr_destroy().

The destroy callback removed each entry from the same IDR being walked.
That is not needed for this cleanup path, and it is unsafe because
idr_for_each() has not advanced its radix-tree iterator while the
callback is running. Removing the current entry from the callback can
invalidate the iterator state. The callback also cannot be protected by
rcu_read_lock(), because scmi_device_destroy() may sleep.

Leave IDR teardown to the following idr_destroy() call and keep the
callback limited to device destruction.