path: root/virt/kvm/assigned-dev.c
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authorJan Kiszka <>2012-01-12 12:39:52 +0200
committerGreg Kroah-Hartman <>2012-01-18 07:31:53 -0800
commit68898049e6b897cd29644c1b500e3e9593805869 (patch)
treebfe9a8d5cce7b52a8f4e9b829b0c0fc2bc65dc58 /virt/kvm/assigned-dev.c
parentda84e453c225f742b32ff68f65fd9a2af2691c7c (diff)
KVM: x86: Prevent starting PIT timers in the absence of irqchip support
(cherry picked from commit 0924ab2cfa98b1ece26c033d696651fd62896c69) 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 <> Signed-off-by: Marcelo Tosatti <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'virt/kvm/assigned-dev.c')
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