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Date:   Sun, 16 Jul 2023 10:12:13 +0700
From:   Bagas Sanjaya <bagasdotme@gmail.com>
To:     Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        hughd@google.com
Cc:     Linux Regressions <regressions@lists.linux.dev>
Subject: Re: [bug/bisected] I see "mm/pgtable-generic.c:53: bad pmd
 (____ptrval____)(8000000100077061)" every boot time
Message-ID: <ZLNgDXj0WfFUOJAJ@debian.me>
References: <CABXGCsN3JqXckWO=V7p=FhPU1tK03RE1w9UE6xL5Y86SMk209w@mail.gmail.com>
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On Sat, Jul 15, 2023 at 02:24:59PM +0500, Mikhail Gavrilov wrote:
> Hi,
> It's ok that I see "mm/pgtable-generic.c:53: bad pmd
> (____ptrval____)(8000000100077061)" every boot time?
> Unfortunately bisect couldn't say which of commits
> # possible first bad commit:
> [be872f83bf571f4f9a0ac25e2c9c36e905a36619] mm/pagewalk:
> walk_pte_range() allow for pte_offset_map()
> # possible first bad commit:
> [7780d04046a2288ab85d88bedacc60fa4fad9971] mm/pagewalkers:
> ACTION_AGAIN if pte_offset_map_lock() fails
> # possible first bad commit:
> [2798bbe75b9c2752b46d292e5c2a49f49da36418] mm/page_vma_mapped:
> pte_offset_map_nolock() not pte_lockptr()
> # possible first bad commit:
> [90f43b0a13cddb09e2686f4d976751c0a9b8b197] mm/page_vma_mapped:
> reformat map_pte() with less indentation
> # possible first bad commit:
> [45fe85e9811ede2d65b21724cae50d6a0563e452] mm/page_vma_mapped: delete
> bogosity in page_vma_mapped_walk()
> # possible first bad commit:
> [65747aaf42b7db6acb8e57a2b8e9959928f404dd] mm/filemap: allow
> pte_offset_map_lock() to fail
> # possible first bad commit:
> [0d940a9b270b9220dcff74d8e9123c9788365751] mm/pgtable: allow
> pte_offset_map[_lock]() to fail
> definitely first bad because my machine on which I am was doing
> bisection is unbootable on these commits.
> I hope Hugh Dickins can figure out what's going on here. He is the
> author of these commits.
>=20
> All mine machines are based on the AMD platform two 7950X and one 5900HX.
>=20
> It seems that this message is harmless for the system in any way, but
> I can't judge it is a bug or not.
> >From the user side it looks like regression because on commit
> 46c475bd676bb05077c8a38b37f175552f035406 this message was absent.

What are you doing on your system that leads into this regression?

Anyway, I'm adding this regression to be tracked with regzbot:

#regzbot ^introduced: 0d940a9b270b92
#regzbot title: undescribed regression due to allowing failing pte_offset_m=
ap[_lock]()

Thanks.

--=20
An old man doll... just what I always wanted! - Clara

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