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commit f6426ab9c957e97418ac5b0466538792767b1738 upstream.
The function amd_ir_set_vcpu_affinity makes use of the parameter struct
amd_iommu_pi_data.prev_ga_tag to determine if it should delete struct
amd_iommu_pi_data from a list when not running in AVIC mode.
However, prev_ga_tag is initialized only when AVIC is enabled. The non-zero
uninitialized value can cause unintended code path, which ends up making
use of the struct vcpu_svm.ir_list and ir_list_lock without being
initialized (since they are intended only for the AVIC case).
This triggers NULL pointer dereference bug in the function vm_ir_list_del
with the following call trace:
svm_update_pi_irte+0x3c2/0x550 [kvm_amd]
? proc_create_single_data+0x41/0x50
kvm_arch_irq_bypass_add_producer+0x40/0x60 [kvm]
__connect+0x5f/0xb0 [irqbypass]
irq_bypass_register_producer+0xf8/0x120 [irqbypass]
vfio_msi_set_vector_signal+0x1de/0x2d0 [vfio_pci]
vfio_msi_set_block+0x77/0xe0 [vfio_pci]
vfio_pci_set_msi_trigger+0x25c/0x2f0 [vfio_pci]
vfio_pci_set_irqs_ioctl+0x88/0xb0 [vfio_pci]
vfio_pci_ioctl+0x2ea/0xed0 [vfio_pci]
? alloc_file_pseudo+0xa5/0x100
vfio_device_fops_unl_ioctl+0x26/0x30 [vfio]
? vfio_device_fops_unl_ioctl+0x26/0x30 [vfio]
__x64_sys_ioctl+0x96/0xd0
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Therefore, initialize prev_ga_tag to zero before use. This should be safe
because ga_tag value 0 is invalid (see function avic_vm_init).
Fixes:
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alpha | ||
arc | ||
arm | ||
arm64 | ||
c6x | ||
csky | ||
h8300 | ||
hexagon | ||
ia64 | ||
m68k | ||
microblaze | ||
mips | ||
nds32 | ||
nios2 | ||
openrisc | ||
parisc | ||
powerpc | ||
riscv | ||
s390 | ||
sh | ||
sparc | ||
um | ||
unicore32 | ||
x86 | ||
xtensa | ||
.gitignore | ||
Kconfig |