Fixes for 4.9

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-4.9/series b/queue-4.9/series
index 355efeafa1d70932c44018e2ff873ac5f55f330d..c29bd8a8f3646cbac102385268e88ebab2d03915 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -15,3 +15,4 @@ scsi-libfc-avoid-invoking-response-handler-twice-if-.patch
 mac80211-fix-fast-rx-encryption-check.patch
 scsi-ibmvfc-set-default-timeout-to-avoid-crash-durin.patch
 objtool-don-t-fail-on-missing-symbol-table.patch
+stable-clamp-sublevel-in-4.4-and-4.9.patch

diff --git a/queue-4.9/stable-clamp-sublevel-in-4.4-and-4.9.patch b/queue-4.9/stable-clamp-sublevel-in-4.4-and-4.9.patch
new file mode 100644 (file)
index 0000000..d41f920
--- /dev/null
+++ b/queue-4.9/stable-clamp-sublevel-in-4.4-and-4.9.patch
@@ -0,0 +1,46 @@
+From 4ad953f1a55ea3823a890a9132d12f3b20d210d6 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 4.4 and 4.9
+
+Right now SUBLEVEL is overflowing, and some userspace may start treating
+4.9.256 as 4.10. 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 4.9 and 4.4 kernels in the form
+of clamping their 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>
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index 69af44d3dcd14..93f7ce06fc8c9 100644
+--- a/Makefile
++++ b/Makefile
+@@ -1141,7 +1141,7 @@ 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
+ 
+-- 
+2.27.0
+