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authorAsias He <asias@redhat.com>2013-05-08 10:57:29 +0800
committerGleb Natapov <gleb@redhat.com>2013-05-08 13:15:35 +0300
commit7dac16c379a876e256bc7349cd80007e7f9f2b59 (patch)
tree47d895c2d9f22b29a79256216706c0397b66023c /virt/kvm/kvm_main.c
parent42bdf991f4cad9678ee2b98c5c2e9299a3f986ef (diff)
downloadlinux-linaro-stable-7dac16c379a876e256bc7349cd80007e7f9f2b59.tar.gz
KVM: Fix kvm_irqfd_init initialization
In commit a0f155e96 'KVM: Initialize irqfd from kvm_init()', when kvm_init() is called the second time (e.g kvm-amd.ko and kvm-intel.ko), kvm_arch_init() will fail with -EEXIST, then kvm_irqfd_exit() will be called on the error handling path. This way, the kvm_irqfd system will not be ready. This patch fix the following: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 PGD 0 Oops: 0002 [#1] SMP Modules linked in: vhost_net CPU 6 Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK RIP: 0010:[<ffffffff81c0721e>] [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 RSP: 0018:ffff880221721cc8 EFLAGS: 00010046 RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950 RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000 RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002 R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8 R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000 FS: 00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640) Stack: ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086 0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000 ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000 Call Trace: [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0 [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0 [<ffffffff810ac949>] queue_work+0x19/0x20 [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60 [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580 [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0 [<ffffffff810c9545>] ? update_curr+0xf5/0x180 [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550 [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0 [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710 [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90 [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f RIP [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30 RSP <ffff880221721cc8> CR2: 0000000000000000 ---[ end trace 13fb1e4b6e5ab21f ]--- Signed-off-by: Asias He <asias@redhat.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 45f09362ee7b..8a1889ccb883 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3105,13 +3105,21 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
int r;
int cpu;
- r = kvm_irqfd_init();
- if (r)
- goto out_irqfd;
r = kvm_arch_init(opaque);
if (r)
goto out_fail;
+ /*
+ * kvm_arch_init makes sure there's at most one caller
+ * for architectures that support multiple implementations,
+ * like intel and amd on x86.
+ * kvm_arch_init must be called before kvm_irqfd_init to avoid creating
+ * conflicts in case kvm is already setup for another implementation.
+ */
+ r = kvm_irqfd_init();
+ if (r)
+ goto out_irqfd;
+
if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
r = -ENOMEM;
goto out_free_0;
@@ -3186,10 +3194,10 @@ out_free_1:
out_free_0a:
free_cpumask_var(cpus_hardware_enabled);
out_free_0:
- kvm_arch_exit();
-out_fail:
kvm_irqfd_exit();
out_irqfd:
+ kvm_arch_exit();
+out_fail:
return r;
}
EXPORT_SYMBOL_GPL(kvm_init);