linux-kernel - Re: [PATCH] mm/hugetlbfs: fix for_each_hstate() loop in init_hugetlbfs

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Message-ID: <a61653f2-64ab-384b-1596-3d2676415786@oracle.com>
Date:   Fri, 3 Jan 2020 09:50:12 -0800
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Jan Stancek <jstancek@...hat.com>, akpm@...ux-foundation.org,
        linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/hugetlbfs: fix for_each_hstate() loop in
 init_hugetlbfs_fs()

On 1/3/20 9:37 AM, Jan Stancek wrote:
> LTP memfd_create04 started failing for some huge page sizes
> after v5.4-10135-gc3bfc5dd73c6.
> 
> Problem is check introduced to for_each_hstate() loop that should
> skip default_hstate_idx. Since it doesn't update 'i' counter, all
> subsequent huge page sizes are skipped as well.
> 
> Fixes: 8fc312b32b25 ("mm/hugetlbfs: fix error handling when setting up mounts")
> Signed-off-by: Jan Stancek <jstancek@...hat.com>

Thank you Jan!

My apologies for a relatively obvious bug.  Testing on x86 did not catch this
as the default hstate is set up last in the list.  Not an excuse, but that is
why I missed it. :(

Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
-- 
Mike Kravetz