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| author | Heyi Guo <guoheyi@huawei.com> | 2019-08-27 12:26:50 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-06 10:19:53 +0200 |
| commit | f35eb8a3aa3b492489116965558c3f2f7d641f31 (patch) | |
| tree | 135860cedbebbfd8af5d7983b438f040db3b7242 | |
| parent | c251d5c53246042dacf485340cb244af92f1f78c (diff) | |
| download | linux-stable-f35eb8a3aa3b492489116965558c3f2f7d641f31.tar.gz linux-stable-f35eb8a3aa3b492489116965558c3f2f7d641f31.tar.bz2 linux-stable-f35eb8a3aa3b492489116965558c3f2f7d641f31.zip | |
KVM: arm/arm64: vgic: Fix potential deadlock when ap_list is long
[ Upstream commit d4a8061a7c5f7c27a2dc002ee4cb89b3e6637e44 ]
If the ap_list is longer than 256 entries, merge_final() in list_sort()
will call the comparison callback with the same element twice, causing
a deadlock in vgic_irq_cmp().
Fix it by returning early when irqa == irqb.
Cc: stable@vger.kernel.org # 4.7+
Fixes: 8e4447457965 ("KVM: arm/arm64: vgic-new: Add IRQ sorting")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Heyi Guo <guoheyi@huawei.com>
[maz: massaged commit log and patch, added Fixes and Cc-stable]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | virt/kvm/arm/vgic/vgic.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index 6440b56ec90e..1934dc8a2ce0 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -196,6 +196,13 @@ static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b) bool penda, pendb; int ret; + /* + * list_sort may call this function with the same element when + * the list is fairly long. + */ + if (unlikely(irqa == irqb)) + return 0; + spin_lock(&irqa->irq_lock); spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING); |