4.19-stable patches

added patches:
	stable-clamp-sublevel-in-4.19.patch

diff --git a/queue-4.19/series b/queue-4.19/series
new file mode 100644 (file)
index 0000000..4c8e350
--- /dev/null
+++ b/queue-4.19/series
@@ -0,0 +1 @@
+stable-clamp-sublevel-in-4.19.patch

diff --git a/queue-4.19/stable-clamp-sublevel-in-4.19.patch b/queue-4.19/stable-clamp-sublevel-in-4.19.patch
new file mode 100644 (file)
index 0000000..9eaf07b
--- /dev/null
+++ b/queue-4.19/stable-clamp-sublevel-in-4.19.patch
@@ -0,0 +1,44 @@
+From e131e0e880f942f138c4b5e6af944c7ddcd7ec96 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Fri, 5 Feb 2021 12:47:02 -0500
+Subject: stable: clamp SUBLEVEL in 4.19
+
+From: Sasha Levin <sashal@kernel.org>
+
+In a few months, SUBLEVEL will overflow, and some userspace may start
+treating 4.19.256 as 4.20. While out of tree modules have different ways
+of extracting the version number (and we're generally ok with breaking
+them), we do care about breaking userspace and it would appear that this
+overflow might do just that.
+
+Our rules around userspace ABI in the stable kernel are pretty simple:
+we don't break it. Thus, while userspace may be checking major/minor, it
+shouldn't be doing anything with sublevel.
+
+This patch applies a big band-aid to the 4.19 kernel in the form of
+clamping the sublevel to 255.
+
+The clamp is done for the purpose of LINUX_VERSION_CODE only, and
+extracting the version number from the Makefile or "make kernelversion"
+will continue to work as intended.
+
+We might need to do it later in newer trees, but maybe we'll have a
+better solution by then, so I'm ignoring that problem for now.
+
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Makefile |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/Makefile
++++ b/Makefile
+@@ -1158,7 +1158,7 @@ endef
+ 
+ define filechk_version.h
+       (echo \#define LINUX_VERSION_CODE $(shell                         \
+-      expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \
++      expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 255); \
+       echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
+ endef
+