Patch "gcov: disable for COMPILE_TEST" has been added to the 4.4-stable tree

Patch "gcov: disable for COMPILE_TEST" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    gcov: disable for COMPILE_TEST

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     gcov-disable-for-compile_test.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From cc622420798c4bcf093785d872525087a7798db9 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 25 Apr 2016 17:35:29 +0200
Subject: gcov: disable for COMPILE_TEST

From: Arnd Bergmann <arnd@arndb.de>

commit cc622420798c4bcf093785d872525087a7798db9 upstream.

Enabling gcov is counterproductive to compile testing: it significantly
increases the kernel image size, compile time, and it produces lots
of false positive "may be used uninitialized" warnings as the result
of missed optimizations.

This is in line with how UBSAN_SANITIZE_ALL and PROFILE_ALL_BRANCHES
work, both of which have similar problems.

With an ARM allmodconfig kernel, I see the build time drop from
283 minutes CPU time to 225 minutes, and the vmlinux size drops
from 43MB to 26MB.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/gcov/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -37,6 +37,7 @@ config ARCH_HAS_GCOV_PROFILE_ALL
 
 config GCOV_PROFILE_ALL
 	bool "Profile entire Kernel"
+	depends on !COMPILE_TEST
 	depends on GCOV_KERNEL
 	depends on ARCH_HAS_GCOV_PROFILE_ALL
 	default n


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/gcov-disable-for-compile_test.patch