From: David Gow davidgow@google.com
[ Upstream commit 7fd53f41f771d250eb08db08650940f017e37c26 ]
kunit_tool maintains a list of config options which are broken under UML, which we exclude from an otherwise 'make ARCH=um allyesconfig' build used to run all tests with the --alltests option.
Something in UML allyesconfig is causing segfaults when page poisining is enabled (and is poisoning with a non-zero value). Previously, this didn't occur, as allyesconfig enabled the CONFIG_PAGE_POISONING_ZERO option, which worked around the problem by zeroing memory. This option has since been removed, and memory is now poisoned with 0xAA, which triggers segfaults in many different codepaths, preventing UML from booting.
Note that we have to disable both CONFIG_PAGE_POISONING and CONFIG_DEBUG_PAGEALLOC, as the latter will 'select' the former on architectures (such as UML) which don't implement __kernel_map_pages().
Ideally, we'd fix this properly by tracking down the real root cause, but since this is breaking KUnit's --alltests feature, it's worth disabling there in the meantime so the kernel can boot to the point where tests can actually run.
Fixes: f289041ed4cf ("mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO") Signed-off-by: David Gow davidgow@google.com Acked-by: Vlastimil Babka vbabka@suse.cz Reviewed-by: Brendan Higgins brendanhiggins@google.com Signed-off-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/kunit/configs/broken_on_uml.config | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/tools/testing/kunit/configs/broken_on_uml.config b/tools/testing/kunit/configs/broken_on_uml.config index a7f0603d33f6..690870043ac0 100644 --- a/tools/testing/kunit/configs/broken_on_uml.config +++ b/tools/testing/kunit/configs/broken_on_uml.config @@ -40,3 +40,5 @@ # CONFIG_RESET_BRCMSTB_RESCAL is not set # CONFIG_RESET_INTEL_GW is not set # CONFIG_ADI_AXI_ADC is not set +# CONFIG_DEBUG_PAGEALLOC is not set +# CONFIG_PAGE_POISONING is not set