Re: [PATCH] ARM64: smp: Fix cpu_up() racing with sys_reboot

2018-07-19 Thread Mark Rutland
On Thu, Jul 19, 2018 at 03:18:46PM -0700, Venkata Narendra Kumar Gutta wrote: > Nothing stops a process from hotplugging in a CPU concurrently > with a sys_reboot() call. In such a situation we could have > ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the > fact that the CPU is not r

Re: [PATCH] ARM64: smp: Fix cpu_up() racing with sys_reboot

2018-07-19 Thread Russell King - ARM Linux
On Thu, Jul 19, 2018 at 03:18:46PM -0700, Venkata Narendra Kumar Gutta wrote: > Nothing stops a process from hotplugging in a CPU concurrently > with a sys_reboot() call. In such a situation we could have > ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the > fact that the CPU is not r

[PATCH] ARM64: smp: Fix cpu_up() racing with sys_reboot

2018-07-19 Thread Venkata Narendra Kumar Gutta
Nothing stops a process from hotplugging in a CPU concurrently with a sys_reboot() call. In such a situation we could have ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the fact that the CPU is not really offline and call the CPU_UP_PREPARE notifier. When this happens stop_machine cod