From: Andrew Morton <akpm@linux-foundation.org>
To: bugs+kernel.org@dtnr.ch
Cc: bugzilla-daemon@bugzilla.kernel.org, linux-mm@kvack.org
Subject: Re: [Bug 213785] New: hugetlbfs scrambles mode when sticky bit is set
Date: Tue, 20 Jul 2021 15:07:04 -0700 [thread overview]
Message-ID: <20210720150704.59f78224be810a0cf9dd5f39@linux-foundation.org> (raw)
In-Reply-To: <bug-213785-27@https.bugzilla.kernel.org/>
(switched to email. Please respond via emailed reply-to-all, not via the
bugzilla web interface).
On Mon, 19 Jul 2021 15:34:00 +0000 bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=213785
>
> Bug ID: 213785
> Summary: hugetlbfs scrambles mode when sticky bit is set
> Product: Memory Management
> Version: 2.5
> Kernel Version: >4.19 (certainly >= 5.4)
> Hardware: All
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: normal
> Priority: P1
> Component: Other
> Assignee: akpm@linux-foundation.org
> Reporter: bugs+kernel.org@dtnr.ch
> Regression: Yes
>
> I noticed the following strange behaviour with hugetlbfs mounts for kernel
> versions something north of 4.19, but certainly since 5.4:
>
> when the mode= option of the mount has the sticky bit set, the mode of the
> mount point gets scrambled.
>
> To test the following command line can be used:
> mkdir -p /tmp/tlbtest && mount -t hugetlbfs -o mode=.... none /tmp/tlbtest &&
> stat -c 'mode: %04a' /tmp/tlbtest
>
> For kernel versions <= 4.19 or if the first byte of mode is 0, stat outputs
> what was set using "-o mode".
>
> But on newer kernel versions if the first byte of mode is 1 the output of stat
> is as follows (input -> output):
> 1700 -> 1244
> 1750 -> 1326
> 1770 -> 1352
> 1775 -> 1357
> 1777 -> 1361
>
> The behaviour is reproducible across different kernel versions and
> architectures (5.4.47-amd64, 5.9.8-amd64, 5.10.40-ppc64el, 5.12.15-amd64).
>
> --
> You may reply to this email to add a comment.
>
> You are receiving this mail because:
> You are the assignee for the bug.
next parent reply other threads:[~2021-07-20 22:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-213785-27@https.bugzilla.kernel.org/>
2021-07-20 22:07 ` Andrew Morton [this message]
2021-07-21 4:38 ` [Bug 213785] New: hugetlbfs scrambles mode when sticky bit is set Mike Kravetz
2021-07-21 7:59 ` [Bug 213785] New: hugetlbfs: interprets mode as decimal (was: hugetlbfs scrambles mode when sticky bit is set) Dennis Camera
2021-07-21 11:57 ` [Bug 213785] New: hugetlbfs scrambles mode when sticky bit is set Matthew Wilcox
2021-07-21 17:48 ` Mike Kravetz
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