From 5ac87c8afd2ae2b1a9fd46a9b80d9152d650fb26 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 6 Dec 2023 10:40:54 +0100 Subject: [PATCH] xen/sched: fix adding offline cpu to cpupool MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Trying to add an offline cpu to a cpupool can crash the hypervisor, as the probably non-existing percpu area of the cpu is accessed before the availability of the cpu is being tested. This can happen in case the cpupool's granularity is "core" or "socket". Fix that by testing the cpu to be online. Fixes: cb563d7665f2 ("xen/sched: support core scheduling for moving cpus to/from cpupools") Reported-by: René Winther Højgaard Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich master commit: 06e8d65d33896aa90f5b6d9b2bce7f11433b33c9 master date: 2023-12-05 09:57:38 +0100 --- xen/common/sched/cpupool.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c index 2e094b0cfa..ad8f608462 100644 --- a/xen/common/sched/cpupool.c +++ b/xen/common/sched/cpupool.c @@ -892,6 +892,8 @@ int cpupool_do_sysctl(struct xen_sysctl_cpupool_op *op) if ( cpu >= nr_cpu_ids ) goto addcpu_out; ret = -ENODEV; + if ( !cpu_online(cpu) ) + goto addcpu_out; cpus = sched_get_opt_cpumask(c->gran, cpu); if ( !cpumask_subset(cpus, &cpupool_free_cpus) || cpumask_intersects(cpus, &cpupool_locked_cpus) )