From: Sasha Levin <sashal@kernel.org>
To: masahiroy@kernel.org, michal.lkml@markovi.net
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, gregkh@linuxfoundation.org,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 2/3] kbuild: clamp SUBLEVEL to 255
Date: Fri, 5 Feb 2021 22:50:32 -0500 [thread overview]
Message-ID: <20210206035033.2036180-2-sashal@kernel.org> (raw)
In-Reply-To: <20210206035033.2036180-1-sashal@kernel.org>
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>
---
Makefile | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
index 49ac1b7fe8e99..157be50c691e5 100644
--- a/Makefile
+++ b/Makefile
@@ -1258,9 +1258,15 @@ 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
--
2.27.0
next prev parent reply other threads:[~2021-02-06 5:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 3:50 [PATCH 1/3] Revert "kbuild: give the SUBLEVEL more room in KERNEL_VERSION" Sasha Levin
2021-02-06 3:50 ` Sasha Levin [this message]
2021-02-06 12:51 ` [PATCH 2/3] kbuild: clamp SUBLEVEL to 255 Greg KH
2021-02-07 2:52 ` Masahiro Yamada
2021-02-08 13:48 ` David Laight
2021-02-08 14:09 ` gregkh
2021-02-08 15:13 ` David Laight
2021-02-09 1:58 ` Masahiro Yamada
2021-02-06 3:50 ` [PATCH 3/3] kbuild: introduce KERNEL_VERSION2 and LINUX_VERSION_CODE2 Sasha Levin
2021-02-06 4:01 ` Sasha Levin
2021-02-06 12:45 ` Masahiro Yamada
2021-02-06 14:31 ` Sasha Levin
2021-02-06 12:53 ` Greg KH
2021-02-06 12:54 ` Greg KH
2021-02-06 12:06 ` [PATCH 1/3] Revert "kbuild: give the SUBLEVEL more room in KERNEL_VERSION" Masahiro Yamada
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