Qualcomm Adreno/KGSL Data Leakage

On Qualcomm Adreno/KGSL builds where CONFIG_QCOM_KGSL_USE_SHMEM is not set (or on older KGSL versions without CONFIG_QCOM_KGSL_USE_SHMEM), KGSL allocates GPU-shared memory from its own page pool. Pages from this pool are inserted into VMAs that don't have any weird flags like VM_PFNMAP set, which means userspace can grab extra references to these pages through get_user_pages() (for example, using vmsplice()). But when GPU-shared memory is freed, KGSL puts the freed pages into its own page pool without checking the page refcount. This …

data data leakage don gpu grab memory own qualcomm weird