linux-toradex.git/tools/testing/cxl/watermark.h, branch master Linux kernel for Apalis and Colibri modules tools/testing/cxl: Prevent cxl_test from confusing production modules 2023-01-05T23:01:45+00:00 Dan Williams dan.j.williams@intel.com 2022-12-13T16:44:24+00:00 8c149eb011be23679b3320d3939f4e3c8271969c The cxl_test machinery builds modified versions of the modules in drivers/cxl/ and intercepts some of their calls to allow cxl_test to inject mock CXL topologies for test. However, if cxl_test attempts the same with production modules, fireworks ensue as Luis discovered [1]. Prevent that scenario by arranging for cxl_test to check for a "watermark" symbol in each of the modules it expects to be modified before the test can run. This turns undefined runtime behavior or crashes into a safer failure to load the cxl_test module. Link: http://lore.kernel.org/r/20221209062919.1096779-1-mcgrof@kernel.org [1] Reported-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> 
The cxl_test machinery builds modified versions of the modules in
drivers/cxl/ and intercepts some of their calls to allow cxl_test to
inject mock CXL topologies for test.

However, if cxl_test attempts the same with production modules,
fireworks ensue as Luis discovered [1]. Prevent that scenario by
arranging for cxl_test to check for a "watermark" symbol in each of the
modules it expects to be modified before the test can run. This turns
undefined runtime behavior or crashes into a safer failure to load the
cxl_test module.

Link: http://lore.kernel.org/r/20221209062919.1096779-1-mcgrof@kernel.org [1]
Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>