diff options
Diffstat (limited to 'sched-kvm-Fix-KVM-preempt_notifier-usage.patch')
| -rw-r--r-- | sched-kvm-Fix-KVM-preempt_notifier-usage.patch | 80 |
1 files changed, 0 insertions, 80 deletions
diff --git a/sched-kvm-Fix-KVM-preempt_notifier-usage.patch b/sched-kvm-Fix-KVM-preempt_notifier-usage.patch deleted file mode 100644 index 958b7fa98..000000000 --- a/sched-kvm-Fix-KVM-preempt_notifier-usage.patch +++ /dev/null @@ -1,80 +0,0 @@ -From: Peter Zijlstra <peterz@infradead.org> -Date: Thu, 25 Jun 2015 14:55:14 +0200 -Subject: [PATCH] sched,kvm: Fix KVM preempt_notifier usage - -The preempt-notifier API needs to sleep with the addition of the -static_key, we do however need to hold off preemption while modifying -the preempt notifier list, otherwise a preemption could observe an -inconsistent list state. - -There is no reason to have preemption disabled in the caller, -registering a preempt notifier is a purely task local affair. - -Therefore move the preempt_disable into the functions and change the -callers to a preemptible context. - -Cc: Gleb Natapov <gleb@kernel.org> -Fixes: 1cde2930e154 ("sched/preempt: Add static_key() to preempt_notifiers") -Reported-and-Tested-by: Pontus Fuchs <pontus.fuchs@gmail.com> -Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> ---- - kernel/sched/core.c | 11 +++++++++++ - virt/kvm/kvm_main.c | 5 +++-- - 2 files changed, 14 insertions(+), 2 deletions(-) - -diff --git a/kernel/sched/core.c b/kernel/sched/core.c -index b803e1b8ab0c..6169c167ac98 100644 ---- a/kernel/sched/core.c -+++ b/kernel/sched/core.c -@@ -2327,7 +2327,12 @@ static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE; - void preempt_notifier_register(struct preempt_notifier *notifier) - { - static_key_slow_inc(&preempt_notifier_key); -+ /* -+ * Avoid preemption while changing the preempt notifier list. -+ */ -+ preempt_disable(); - hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); -+ preempt_enable(); - } - EXPORT_SYMBOL_GPL(preempt_notifier_register); - -@@ -2339,7 +2344,13 @@ EXPORT_SYMBOL_GPL(preempt_notifier_register); - */ - void preempt_notifier_unregister(struct preempt_notifier *notifier) - { -+ /* -+ * Avoid preemption while changing the preempt notifier list. -+ */ -+ preempt_disable(); - hlist_del(¬ifier->link); -+ preempt_enable(); -+ - static_key_slow_dec(&preempt_notifier_key); - } - EXPORT_SYMBOL_GPL(preempt_notifier_unregister); -diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c -index 848af90b8091..7dc8d3eb9e1f 100644 ---- a/virt/kvm/kvm_main.c -+++ b/virt/kvm/kvm_main.c -@@ -127,8 +127,9 @@ int vcpu_load(struct kvm_vcpu *vcpu) - - if (mutex_lock_killable(&vcpu->mutex)) - return -EINTR; -- cpu = get_cpu(); - preempt_notifier_register(&vcpu->preempt_notifier); -+ -+ cpu = get_cpu(); - kvm_arch_vcpu_load(vcpu, cpu); - put_cpu(); - return 0; -@@ -138,8 +139,8 @@ void vcpu_put(struct kvm_vcpu *vcpu) - { - preempt_disable(); - kvm_arch_vcpu_put(vcpu); -- preempt_notifier_unregister(&vcpu->preempt_notifier); - preempt_enable(); -+ preempt_notifier_unregister(&vcpu->preempt_notifier); - mutex_unlock(&vcpu->mutex); - } - |