From 9b82f13e7ef316cdc0a8858f1349f4defce3f9e0 Mon Sep 17 00:00:00 2001 From: Sasha Levin <sashal@kernel.org> Date: Fri, 5 Feb 2021 22:50:32 -0500 Subject: [PATCH] kbuild: clamp SUBLEVEL to 255 Right now if SUBLEVEL becomes larger than 255 it will overflow into the territory of PATCHLEVEL, causing havoc in userspace that tests for specific kernel version. While userspace code tests for MAJOR and PATCHLEVEL, it doesn't test SUBLEVEL at any point as ABI changes don't happen in the context of stable tree. Thus, to avoid overflows, simply clamp SUBLEVEL to it's maximum value in the context of LINUX_VERSION_CODE. This does not affect "make kernelversion" and such. Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Makefile | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 681bdb5d2f41e..12607d3891487 100644 --- a/Makefile +++ b/Makefile @@ -1247,9 +1247,15 @@ define filechk_utsrelease.h endef define filechk_version.h - echo \#define LINUX_VERSION_CODE $(shell \ - expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \ - echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))' + if [ $(SUBLEVEL) -gt 255 ]; then \ + echo \#define LINUX_VERSION_CODE $(shell \ + expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 255); \ + else \ + echo \#define LINUX_VERSION_CODE $(shell \ + expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + $(SUBLEVEL)); \ + fi; \ + echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + \ + ((c) > 255 ? 255 : (c)))' endef $(version_h): FORCE -- 2.30.2