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| author | Davidlohr Bueso <dave@stgolabs.net> | 2017-09-13 13:08:24 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-09-15 16:57:13 +0200 |
| commit | 4c0b4bc60f95de4741c89b41174760258343f091 (patch) | |
| tree | 60a9e39653ad9d755c962633f8ea63c4b88f76f1 | |
| parent | 267ad7bc2d3f69af536035b6a3e4a9a2b6ae11dc (diff) | |
| download | linux-stable-4c0b4bc60f95de4741c89b41174760258343f091.tar.gz linux-stable-4c0b4bc60f95de4741c89b41174760258343f091.tar.bz2 linux-stable-4c0b4bc60f95de4741c89b41174760258343f091.zip | |
kvm,mips: Fix potential swait_active() races
For example, the following could occur, making us miss a wakeup:
CPU0 CPU1
kvm_vcpu_block kvm_mips_comparecount_func
[L] swait_active(&vcpu->wq)
[S] prepare_to_swait(&vcpu->wq)
[L] if (!kvm_vcpu_has_pending_timer(vcpu))
schedule() [S] queue_timer_int(vcpu)
Ensure that the swait_active() check is not hoisted over the interrupt.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/mips/kvm/mips.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index bce2a6431430..d535edc01434 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -514,7 +514,7 @@ int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, dvcpu->arch.wait = 0; - if (swait_active(&dvcpu->wq)) + if (swq_has_sleeper(&dvcpu->wq)) swake_up(&dvcpu->wq); return 0; @@ -1179,7 +1179,7 @@ static void kvm_mips_comparecount_func(unsigned long data) kvm_mips_callbacks->queue_timer_int(vcpu); vcpu->arch.wait = 0; - if (swait_active(&vcpu->wq)) + if (swq_has_sleeper(&vcpu->wq)) swake_up(&vcpu->wq); } |