[merged] lib-ubsan-default-ubsan_alignment-to-not-set.patch removed from -mm tree

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The patch titled
     Subject: lib/ubsan: default UBSAN_ALIGNMENT to not set
has been removed from the -mm tree.  Its filename was
     lib-ubsan-default-ubsan_alignment-to-not-set.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Anders Roxell <anders.roxell@xxxxxxxxxx>
Subject: lib/ubsan: default UBSAN_ALIGNMENT to not set

When booting an allmodconfig kernel, there are a lot of false-positives. 
With a message like this 'UBSAN: Undefined behaviour in...' with a call
trace that follows.

UBSAN warnings are a result of enabling noisy CONFIG_UBSAN_ALIGNMENT
which is disabled by default if HAVE_EFFICIENT_UNALIGNED_ACCESS=y.

It's noisy even if don't have efficient unaligned access, e.g.  people
often add __cacheline_aligned_in_smp in structs, but forget to align
allocations of such struct (kmalloc() give 8-byte alignment in worst
case).

Rework so that when building a allmodconfig kernel that turns
everything into '=m' or '=y' will turn off UBSAN_ALIGNMENT.

[aryabinin@xxxxxxxxxxxxx: changelog addition]
Link: http://lkml.kernel.org/r/20181217150326.30933-1-anders.roxell@xxxxxxxxxx
Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---


--- a/lib/Kconfig.ubsan~lib-ubsan-default-ubsan_alignment-to-not-set
+++ a/lib/Kconfig.ubsan
@@ -27,15 +27,19 @@ config UBSAN_SANITIZE_ALL
 	  Enabling this option will get kernel image size increased
 	  significantly.
 
-config UBSAN_ALIGNMENT
-	bool "Enable checking of pointers alignment"
+config UBSAN_NO_ALIGNMENT
+	bool "Disable checking of pointers alignment"
 	depends on UBSAN
-	default y if !HAVE_EFFICIENT_UNALIGNED_ACCESS
+	default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
 	help
-	  This option enables detection of unaligned memory accesses.
-	  Enabling this option on architectures that support unaligned
+	  This option disables the check of unaligned memory accesses.
+	  This option should be used when building allmodconfig.
+	  Disabling this option on architectures that support unaligned
 	  accesses may produce a lot of false positives.
 
+config UBSAN_ALIGNMENT
+	def_bool !UBSAN_NO_ALIGNMENT
+
 config TEST_UBSAN
 	tristate "Module for testing for undefined behavior detection"
 	depends on m && UBSAN
_

Patches currently in -mm which might be from anders.roxell@xxxxxxxxxx are

treewide-add-checks-for-the-return-value-of-memblock_alloc-fix.patch




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