In the Linux kernel, the following vulnerability has been resolved:
stackdepot: fix stack_depot_save_flags() in NMI context
Per documentation, stack_depot_save_flags() was meant to be usable from NMI context if STACK_DEPOT_FLAG_CAN_ALLOC is unset. However, it still would try to take the pool_lock in an attempt to save a stack trace in the current pool (if space is available).
This could result in deadlock if an NMI is handled while pool_lock is already held. To avoid deadlock, only try to take the lock in NMI context and give up if unsuccessful.
The documentation is fixed to clearly convey this.