This is a note to let you know that I've just added the patch titled
KVM: x86: Prevent starting PIT timers in the absence of irqchip support
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-prevent-starting-pit-timers-in-the-absence-of-irqchip-support.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From jslaby@xxxxxxx Mon Apr 1 16:36:34 2013
From: Jiri Slaby <jslaby@xxxxxxx>
Date: Tue, 19 Mar 2013 12:36:51 +0100
Subject: KVM: x86: Prevent starting PIT timers in the absence of irqchip support
To: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: jirislaby@xxxxxxxxx, stable@xxxxxxxxxxxxxxx, Jan Kiszka <jan.kiszka@xxxxxxxxxxx>, Marcelo Tosatti <mtosatti@xxxxxxxxxx>, Jiri Slaby <jslaby@xxxxxxx>
Message-ID: <1363693019-14812-6-git-send-email-jslaby@xxxxxxx>
From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
commit 0924ab2cfa98b1ece26c033d696651fd62896c69 upstream.
User space may create the PIT and forgets about setting up the irqchips.
In that case, firing PIT IRQs will crash the host:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000128
IP: [<ffffffffa10f6280>] kvm_set_irq+0x30/0x170 [kvm]
...
Call Trace:
[<ffffffffa11228c1>] pit_do_work+0x51/0xd0 [kvm]
[<ffffffff81071431>] process_one_work+0x111/0x4d0
[<ffffffff81071bb2>] worker_thread+0x152/0x340
[<ffffffff81075c8e>] kthread+0x7e/0x90
[<ffffffff815a4474>] kernel_thread_helper+0x4/0x10
Prevent this by checking the irqchip mode before starting a timer. We
can't deny creating the PIT if the irqchips aren't set up yet as
current user land expects this order to work.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/i8254.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -338,11 +338,15 @@ static enum hrtimer_restart pit_timer_fn
return HRTIMER_NORESTART;
}
-static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
+static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
{
+ struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
struct kvm_timer *pt = &ps->pit_timer;
s64 interval;
+ if (!irqchip_in_kernel(kvm))
+ return;
+
interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
pr_debug("create pit timer, interval is %llu nsec\n", interval);
@@ -394,13 +398,13 @@ static void pit_load_count(struct kvm *k
/* FIXME: enhance mode 4 precision */
case 4:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
- create_pit_timer(ps, val, 0);
+ create_pit_timer(kvm, val, 0);
}
break;
case 2:
case 3:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
- create_pit_timer(ps, val, 1);
+ create_pit_timer(kvm, val, 1);
}
break;
default:
Patches currently in stable-queue which might be from jslaby@xxxxxxx are
queue-3.0/kvm-x86-prevent-starting-pit-timers-in-the-absence-of-irqchip-support.patch
queue-3.0/kvm-x86-invalid-opcode-oops-on-set_sregs-with-osxsave-bit-set-cve-2012-4461.patch
queue-3.0/mm-hotplug-correctly-add-new-zone-to-all-other-nodes-zone-lists.patch
queue-3.0/macvtap-zerocopy-validate-vectors-before-building-skb.patch
queue-3.0/x25-validate-incoming-call-user-data-lengths.patch
queue-3.0/batman-adv-bat_socket_read-missing-checks.patch
queue-3.0/kvm-fix-buffer-overflow-in-kvm_set_irq.patch
queue-3.0/x25-handle-undersized-fragmented-skbs.patch
queue-3.0/nfsv4-include-bitmap-in-nfsv4-get-acl-data.patch
queue-3.0/nfs-nfs_getaclargs.acl_len-is-a-size_t.patch
queue-3.0/nfsv4-fix-an-oops-in-the-nfsv4-getacl-code.patch
queue-3.0/kvm-clean-up-error-handling-during-vcpu-creation.patch
queue-3.0/kvm-ensure-all-vcpus-are-consistent-with-in-kernel-irqchip-settings.patch
queue-3.0/batman-adv-only-write-requested-number-of-byte-to-user-buffer.patch
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