Re: [PATCH] powerpc/64s/hash: Make hash faults work in NMI context

2022-03-02 Thread Michael Ellerman
On Fri, 4 Feb 2022 13:53:48 +1000, Nicholas Piggin wrote: > Hash faults are not resoved in NMI context, instead causing the access > to fail. This is done because perf interrupts can get backtraces > including walking the user stack, and taking a hash fault on those could > deadlock on the HPTE loc

Re: [PATCH] powerpc/64s/hash: Make hash faults work in NMI context

2022-02-03 Thread Aneesh Kumar K.V
Nicholas Piggin writes: > Hash faults are not resoved in NMI context, instead causing the access > to fail. This is done because perf interrupts can get backtraces > including walking the user stack, and taking a hash fault on those could > deadlock on the HPTE lock if the perf interrupt hits whi

[PATCH] powerpc/64s/hash: Make hash faults work in NMI context

2022-02-03 Thread Nicholas Piggin
Hash faults are not resoved in NMI context, instead causing the access to fail. This is done because perf interrupts can get backtraces including walking the user stack, and taking a hash fault on those could deadlock on the HPTE lock if the perf interrupt hits while the same HPTE lock is being hel