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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 10:23:41 +0200 |
| commit | ea93e118ef2eb04b348f2c65149665533ea9b1e6 (patch) | |
| tree | f7ab179cf66a22d057c7e17d836a846210dfc8bc /virt | |
| parent | d69ebe85e16908698844c40f08d3d1dba417405c (diff) | |
| download | linux-stable-ea93e118ef2eb04b348f2c65149665533ea9b1e6.tar.gz linux-stable-ea93e118ef2eb04b348f2c65149665533ea9b1e6.tar.bz2 linux-stable-ea93e118ef2eb04b348f2c65149665533ea9b1e6.zip | |
KVM: arm/arm64: vgic: Fix potential deadlock when ap_list is long
commit d4a8061a7c5f7c27a2dc002ee4cb89b3e6637e44 upstream.
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
| -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 13d4b38a94ec..e7bde65ba67c 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -254,6 +254,13 @@ 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; + raw_spin_lock(&irqa->irq_lock); raw_spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING); |