On Fri, 22 Nov 2024 16:39:47 +0100 Marco Elver <elver@xxxxxxxxxx> wrote: > 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. Is it possible to trigger this deadlock in current kernels, or is this a might-happen-in-the-future thing? > The documentation is fixed to clearly convey this. >
