From: Hugh Dickins <hughd@google.com>
To: Patrice CHOTARD <patrice.chotard@foss.st.com>
Cc: hughd@google.com, mpatocka@redhat.com, lczerner@redhat.com,
djwong@kernel.org, hch@lst.de, zkabelac@redhat.com,
miklos@szeredi.hu, bp@suse.de, akpm@linux-foundation.org,
Alexandre TORGUE - foss <alexandre.torgue@foss.st.com>,
Valentin CARON - foss <valentin.caron@foss.st.com>,
linux-stm32@st-md-mailman.stormreply.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Regression with v5.18-rc1 tag on STM32F7 and STM32H7 based boards
Date: Tue, 5 Apr 2022 12:59:41 -0700 (PDT) [thread overview]
Message-ID: <95a0d1dd-bcce-76c7-97b9-8374c9913321@google.com> (raw)
In-Reply-To: <481a13f8-d339-f726-0418-ab4258228e91@foss.st.com>
On Tue, 5 Apr 2022, Patrice CHOTARD wrote:
>
> We found an issue with last kernel tag v5.18-rc1 on stm32f746-disco and
> stm32h743-disco boards (ARMV7-M SoCs).
>
> Kernel hangs when executing SetPageUptodate(ZERO_PAGE(0)); in mm/filemap.c.
>
> By reverting commit 56a8c8eb1eaf ("tmpfs: do not allocate pages on read"),
> kernel boots without any issue.
Sorry about that, thanks a lot for finding.
I see that arch/arm/configs/stm32_defconfig says CONFIG_MMU is not set:
please confirm that is the case here.
Yes, it looks as if NOMMU platforms are liable to have a bogus (that's my
reading, but it may be unfair) definition for ZERO_PAGE(vaddr), and I was
walking on ice to touch it without regard for !CONFIG_MMU.
CONFIG_SHMEM depends on CONFIG_MMU, so that PageUptodate is only needed
when CONFIG_MMU.
Easily fixed by an #ifdef CONFIG_MMU there in mm/filemap.c, but I'll hunt
around (again) for a better place to do it - though I won't want to touch
all the architectures for it. I'll post later today.
Hugh
next prev parent reply other threads:[~2022-04-05 20:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 15:15 Patrice CHOTARD
2022-04-05 19:59 ` Hugh Dickins [this message]
2022-04-06 6:20 ` Patrice CHOTARD
2022-04-06 6:22 ` Hugh Dickins
2022-04-06 7:01 ` Patrice CHOTARD
2022-04-16 0:58 ` Hugh Dickins
2022-04-20 13:52 ` Greg Ungerer
2022-04-20 14:44 ` Geert Uytterhoeven
2022-04-21 12:02 ` Greg Ungerer
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