title: powerpc/pseries/iommu: DLPAR add doesn't completely initialize pci_controller
description: In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries/iommu: DLPAR add doesn't completely initialize pci_controller
When a PCI device is dynamically added, the kernel oopses with a NULL
pointer dereference:
BUG: Kernel NULL pointer dereference on read at 0x00000030
Faulting instruction address: 0xc0000000006bbe5c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs xsk_diag bonding nft_compat nf_tables nfnetlink rfkill binfmt_misc dm_multipath rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_umad ib_iser libiscsi scsi_transport_iscsi ib_ipoib rdma_cm iw_cm ib_cm mlx5_ib ib_uverbs ib_core pseries_rng drm drm_panel_orientation_quirks xfs libcrc32c mlx5_core mlxfw sd_mod t10_pi sg tls ibmvscsi ibmveth scsi_transport_srp vmx_crypto pseries_wdt psample dm_mirror dm_region_hash dm_log dm_mod fuse
CPU: 17 PID: 2685 Comm: drmgr Not tainted 6.7.0-203405+ #66
Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries
NIP:  c0000000006bbe5c LR: c000000000a13e68 CTR: c0000000000579f8
REGS: c00000009924f240 TRAP: 0300   Not tainted  (6.7.0-203405+)
MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 24002220  XER: 20040006
CFAR: c000000000a13e64 DAR: 0000000000000030 DSISR: 40000000 IRQMASK: 0
...
NIP sysfs_add_link_to_group+0x34/0x94
LR  iommu_device_link+0x5c/0x118
Call Trace:
iommu_init_device+0x26c/0x318 (unreliable)
iommu_device_link+0x5c/0x118
iommu_init_device+0xa8/0x318
iommu_probe_device+0xc0/0x134
iommu_bus_notifier+0x44/0x104
notifier_call_chain+0xb8/0x19c
blocking_notifier_call_chain+0x64/0x98
bus_notify+0x50/0x7c
device_add+0x640/0x918
pci_device_add+0x23c/0x298
of_create_pci_dev+0x400/0x884
of_scan_pci_dev+0x124/0x1b0
__of_scan_bus+0x78/0x18c
pcibios_scan_phb+0x2a4/0x3b0
init_phb_dynamic+0xb8/0x110
dlpar_add_slot+0x170/0x3b8 [rpadlpar_io]
add_slot_store.part.0+0xb4/0x130 [rpadlpar_io]
kobj_attr_store+0x2c/0x48
sysfs_kf_write+0x64/0x78
kernfs_fop_write_iter+0x1b0/0x290
vfs_write+0x350/0x4a0
ksys_write+0x84/0x140
system_call_exception+0x124/0x330
system_call_vectored_common+0x15c/0x2ec
Commit a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities
and allow blocking domains") broke DLPAR add of PCI devices.
The above added iommu_device structure to pci_controller. During
system boot, PCI devices are discovered and this newly added iommu_device
structure is initialized by a call to iommu_device_register().
During DLPAR add of a PCI device, a new pci_controller structure is
allocated but there are no calls made to iommu_device_register()
interface.
Fix is to register the iommu device during DLPAR add as well.
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: a940904443e4, lessThan: b8315b2e25b4, status: affected, versionType: git
version: a940904443e4, lessThan: 46e36ebd5e00, status: affected, versionType: git
version: a940904443e4, lessThan: a5c57fd2e9bd, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 6.4, status: affected
version: 0, lessThan: 6.4, status: unaffected, versionType: custom
version: 6.6.19, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.7, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
