Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

wifi: ath11k: fix deinitialization of firmware resources

Currently, in ath11k_ahb_fw_resources_init(), iommu domain mapping is done only for the chipsets having fixed firmware memory. Also, for such chipsets, mapping is done only if it does not have TrustZone support.

During deinitialization, only if TrustZone support is not there, iommu is unmapped back. However, for non fixed firmware memory chipsets, TrustZone support is not there and this makes the condition check to true and it tries to unmap the memory which was not mapped during initialization.

This leads to the following trace -

[ 83.198790] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 [ 83.259537] Modules linked in: ath11k_ahb ath11k qmi_helpers .. snip .. [ 83.280286] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 83.287228] pc : __iommu_unmap+0x30/0x140 [ 83.293907] lr : iommu_unmap+0x5c/0xa4 [ 83.298072] sp : ffff80000b3abad0 .. snip .. [ 83.369175] Call trace: [ 83.376282] __iommu_unmap+0x30/0x140 [ 83.378541] iommu_unmap+0x5c/0xa4 [ 83.382360] ath11k_ahb_fw_resource_deinit.part.12+0x2c/0xac [ath11k_ahb] [ 83.385666] ath11k_ahb_free_resources+0x140/0x17c [ath11k_ahb] [ 83.392521] ath11k_ahb_shutdown+0x34/0x40 [ath11k_ahb] [ 83.398248] platform_shutdown+0x20/0x2c [ 83.403455] device_shutdown+0x16c/0x1c4 [ 83.407621] kernel_restart_prepare+0x34/0x…