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On ARM64, park_offline_cpus is always false, so setting __per_cpu_offset to INVALID_PERCPU_AREA depends solely on the system state. If the system is suspended, this area is not freed, and during resume, an error occurs in init_percpu_area, causing a crash because INVALID_PERCPU_AREA is not set and park_offline_cpus remains 0: if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) return park_offline_cpus ? 0 : -EBUSY; It appears that the same crash can occur on x86 if park_offline_cpus is set to 0 during Xen suspend. Signed-off-by: Mykyta Poturai Signed-off-by: Mykola Kvach Reviewed-by: Jan Beulich --- Discussion related to these changes can be found here: https://marc.info/?l=xen-devel&m=174116563705295&w=2 --- xen/common/percpu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/xen/common/percpu.c b/xen/common/percpu.c index e4e8b7bcab..607557436d 100644 --- a/xen/common/percpu.c +++ b/xen/common/percpu.c @@ -30,7 +30,12 @@ static int init_percpu_area(unsigned int cpu) char *p; if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) - return park_offline_cpus ? 0 : -EBUSY; + { + if ( system_state == SYS_STATE_resume ) + return 0; + else + return park_offline_cpus ? 0 : -EBUSY; + } if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL ) return -ENOMEM;