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Subject: Re: [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>,
        libhugetlbfs@googlegroups.com
References: <20171129144219.22867-1-mhocko@kernel.org>
 <20171129144219.22867-3-mhocko@kernel.org>
 <93ce964b-e352-1905-c2b6-deedf2ea06f8@oracle.com>
From:   Mike Kravetz <mike.kravetz@oracle.com>
Message-ID: <c0e447b3-4ba7-239e-6550-64de7721ad28@oracle.com>
Date:   Tue, 29 May 2018 15:21:14 -0700
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Just a quick heads up.  I noticed a change in libhugetlbfs testing starting
with v4.17-rc1.

V4.16 libhugetlbfs test results
********** TEST SUMMARY
*                      2M            
*                      32-bit 64-bit 
*     Total testcases:   110    113   
*             Skipped:     0      0   
*                PASS:   105    111   
*                FAIL:     0      0   
*    Killed by signal:     4      1   
*   Bad configuration:     1      1   
*       Expected FAIL:     0      0   
*     Unexpected PASS:     0      0   
*    Test not present:     0      0   
* Strange test result:     0      0   
**********

v4.17-rc1 (and later) libhugetlbfs test results
********** TEST SUMMARY
*                      2M            
*                      32-bit 64-bit 
*     Total testcases:   110    113   
*             Skipped:     0      0   
*                PASS:    98    111   
*                FAIL:     0      0   
*    Killed by signal:    11      1   
*   Bad configuration:     1      1   
*       Expected FAIL:     0      0   
*     Unexpected PASS:     0      0   
*    Test not present:     0      0   
* Strange test result:     0      0   
**********

I traced the 7 additional (32-bit) killed by signal results to this
commit 4ed28639519c fs, elf: drop MAP_FIXED usage from elf_map.

libhugetlbfs does unusual things and even provides custom linker scripts.
So, in hindsight this change in behavior does not seem too unexpected.  I
JUST discovered this while running libhugetlbfs tests for an unrelated
issue/change and, will do some analysis to see exactly what is happening.

Also, will take it upon myself to run libhugetlbfs test suite on a
regular (at least weekly) basis.
-- 
Mike Kravetz