Hello Andrew,
This patch fixes deadlock of stop_machine() vs. synchronous IPI send.
The problem is that stop_machine() disables interrupts before disabling
preemption on other CPUs. So if another CPU is preempted and then calls
something like flush_tlb_all() it will deadlock with CPU doing
stop_machine() and which can't process IPI due to disabled IRQs.
I changed stop_machine() to do the same things exactly as it does on
other CPUs, i.e. it should disable preemption first on _all_ CPUs
including itself and only after that disable IRQs.
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Kirill
This patch fixes deadlock of stop_machine() vs. synchronous IPI send.
The problem is that stop_machine() disables interrupts before disabling
preemption on other CPUs. So if another CPU is preempted and then calls
something like flush_tlb_all() it will deadlock with CPU doing
stop_machine() and which can't process IPI due to disabled IRQs.
I changed stop_machine() to do the same things exactly as it does on
other CPUs, i.e. it should disable preemption first on _all_ CPUs
including itself and only after that disable IRQs.
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Kirill