From: Alison Schofield Date: Fri, 9 Jan 2026 19:49:44 +0000 (-0800) Subject: cxl/acpi: Restore HBIW check before dereferencing platform_data X-Git-Tag: v6.19-rc6~21^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=49d106347913201b6bc6d810c964b90781db8343;p=thirdparty%2Flinux.git cxl/acpi: Restore HBIW check before dereferencing platform_data Commit 4fe516d2ad1a ("cxl/acpi: Make the XOR calculations available for testing") split xormap handling code to create a reusable helper function but inadvertently dropped the check of HBIW values before dereferencing cxlrd->platform_data. When HBIW is 1 or 3, no xormaps are needed and platform_data may be NULL, leading to a potential NULL pointer dereference. Affects platform configs using XOR Arithmetic with HBIWs of 1 or 3, when performing DPA->HPA address translation for CXL events. Those events would be any of poison ops, general media, or dram. Restore the early return check for HBIW values of 1 and 3 before dereferencing platform_data. Fixes: 4fe516d2ad1a ("cxl/acpi: Make the XOR calculations available for testing") Signed-off-by: Alison Schofield Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260109194946.431083-1-alison.schofield@intel.com Signed-off-by: Dave Jiang --- diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index 77ac940e3013..49bba2b9a3c4 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -75,9 +75,16 @@ EXPORT_SYMBOL_FOR_MODULES(cxl_do_xormap_calc, "cxl_translate"); static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr) { - struct cxl_cxims_data *cximsd = cxlrd->platform_data; + int hbiw = cxlrd->cxlsd.nr_targets; + struct cxl_cxims_data *cximsd; + + /* No xormaps for host bridge interleave ways of 1 or 3 */ + if (hbiw == 1 || hbiw == 3) + return addr; + + cximsd = cxlrd->platform_data; - return cxl_do_xormap_calc(cximsd, addr, cxlrd->cxlsd.nr_targets); + return cxl_do_xormap_calc(cximsd, addr, hbiw); } struct cxl_cxims_context {