Re: [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map

From: Mike Kravetz
Date: Tue May 29 2018 - 18:21:33 EST


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