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Subject: Re: [gcov_module_notifier] WARNING: CPU: 0 PID: 155 at
 mm/slab_common.c:996 kmalloc_slab+0x1f/0x79
To:     Fengguang Wu <fengguang.wu@intel.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Riku Voipio <riku.voipio@linaro.org>,
        Frantisek Hrbata <fhrbata@redhat.com>,
        Masahiro Yamada <yamada.m@jp.panasonic.com>,
        linux-kernel@vger.kernel.org, lkp@01.org
References: <20180419025854.uasnqkaflr45zeat@wfg-t540p.sh.intel.com>
From:   Peter Oberparleiter <oberpar@linux.ibm.com>
Date:   Fri, 20 Apr 2018 13:08:07 +0200
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On 19.04.2018 04:58, Fengguang Wu wrote:
> FYI this happens in mainline kernel 4.17.0-rc1.
> It at least dates back to v4.5 .

This is likely the result of compiling the kernel with GCC 7 while
specifying that gcov-kernel should expect GCC <= 3.4 format data:

dmesg:
> (gcc version 7.3.0 (Debian 7.3.0-1)) #31 Mon Apr 16 23:17:50 CST 2018

.config:
> # CONFIG_GCOV_FORMAT_AUTODETECT is not set
> CONFIG_GCOV_FORMAT_3_4=y
> # CONFIG_GCOV_FORMAT_4_7 is not set

As such, it is an expected test failure. Assuming that this is a
randconfig test, my recommendation would be to blacklist
"CONFIG_GCOV_FORMAT_3_4=y" when using GCC >3.4.

-- 
Peter Oberparleiter
Linux on Z Development - IBM Germany