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Translation functions may return an invalid address in case of errors. If the address is not checked the further use of the invalid value will cause an address corruption. Consistently check for a valid address returned by translation functions. Use RESOURCE_SIZE_MAX to indicate an invalid address for type resource_size_t. Depending on the type either RESOURCE_SIZE_MAX or ULLONG_MAX is used to indicate an address error. Propagating an invalid address from a failed translation may cause userspace to think it has received a valid SPA, when in fact it is wrong. The CXL userspace API, using trace events, expects ULLONG_MAX to indicate a translation failure. If ULLONG_MAX is not returned immediately, subsequent calculations can transform that bad address into a different value (!ULLONG_MAX), and an invalid SPA may be returned to userspace. This can lead to incorrect diagnostics and erroneous corrective actions. [ dj: Added user impact statement from Alison. ] [ dj: Fixed checkpatch tab alignment issue. ] Reviewed-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Robert Richter <rrichter@amd.com> Fixes:c3dd67681c("cxl/region: Add inject and clear poison by region offset") Fixes:b78b9e7b79("cxl/region: Refactor address translation funcs for testing") Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> Link: https://patch.msgid.link/20260107120544.410993-1-rrichter@amd.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>