cxl/acpi: Fix a use-after-free in cxl_parse_cfmws()

KASAN and KFENCE detected an user-after-free in the CXL driver. This
happens in the cxl_decoder_add() fail path. KASAN prints the following
error:

   BUG: KASAN: slab-use-after-free in cxl_parse_cfmws (drivers/cxl/acpi.c:299)

This happens in cxl_parse_cfmws(), where put_device() is called,
releasing cxld, which is accessed later.

Use the local variables in the dev_err() instead of pointing to the
released memory. Since the dev_err() is printing a resource, change the open
coded print format to use the %pr format specifier.

Fixes: e50fe01e1f2a ("cxl/core: Drop ->platform_res attribute for root decoders")
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230714093146.2253438-1-leitao@debian.org
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 658e6b8..33c073f 100644 (file)
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -296,8 +296,7 @@ err_xormap:
        else
                rc = cxl_decoder_autoremove(dev, cxld);
        if (rc) {
-               dev_err(dev, "Failed to add decode range [%#llx - %#llx]\n",
-                       cxld->hpa_range.start, cxld->hpa_range.end);
+               dev_err(dev, "Failed to add decode range: %pr", res);
                return 0;
        }
        dev_dbg(dev, "add: %s node: %d range [%#llx - %#llx]\n",