diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-11-13 12:51:11 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-19 13:11:50 +0100 |
| commit | e35aaf3e8f921134659a4b94ce6e3fa1c4f3510d (patch) | |
| tree | 9a3baf9a0c181f40a1b6fceb3fe5c1f698e4f97d /arch | |
| parent | d061be4c8040ffb1110d537654a038b8b6ad39d2 (diff) | |
KVM: x86: WARN if hrtimer callback for periodic APIC timer fires with period=0
commit 0ea9494be9c931ddbc084ad5e11fda91b554cf47 upstream.
WARN and don't restart the hrtimer if KVM's callback runs with the guest's
APIC timer in periodic mode but with a period of '0', as not advancing the
hrtimer's deadline would put the CPU into an infinite loop of hrtimer
events. Observing a period of '0' should be impossible, even when the
hrtimer is running on a different CPU than the vCPU, as KVM is supposed to
cancel the hrtimer before changing (or zeroing) the period, e.g. when
switching from periodic to one-shot.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251113205114.1647493-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index fdbca15ecb44..a6b893c74dc0 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2434,7 +2434,7 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data) apic_timer_expired(apic, true); - if (lapic_is_periodic(apic)) { + if (lapic_is_periodic(apic) && !WARN_ON_ONCE(!apic->lapic_timer.period)) { advance_periodic_target_expiration(apic); hrtimer_add_expires_ns(&ktimer->timer, ktimer->period); return HRTIMER_RESTART; |