From: Thomas Gleixner <tglx@linutronix.de>
To: Hugh Dickins <hughd@google.com>,
Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <brauner@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@lst.de>,
Kent Overstreet <kent.overstreet@linux.dev>,
"Darrick J. Wong" <djwong@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@linuxfoundation.org>
Subject: Re: [PATCH] iov_iter: fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP
Date: Mon, 28 Oct 2024 09:41:48 +0100 [thread overview]
Message-ID: <874j4w4o1f.ffs@tglx> (raw)
In-Reply-To: <dd5f0c89-186e-18e1-4f43-19a60f5a9774@google.com>
On Sun, Oct 27 2024 at 15:23, Hugh Dickins wrote:
> generic/077 on x86_32 CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP=y with highmem,
> on huge=always tmpfs, issues a warning and then hangs (interruptibly):
>
> WARNING: CPU: 5 PID: 3517 at mm/highmem.c:622 kunmap_local_indexed+0x62/0xc9
> CPU: 5 UID: 0 PID: 3517 Comm: cp Not tainted 6.12.0-rc4 #2
> ...
> copy_page_from_iter_atomic+0xa6/0x5ec
> generic_perform_write+0xf6/0x1b4
> shmem_file_write_iter+0x54/0x67
>
> Fix copy_page_from_iter_atomic() by limiting it in that case
> (include/linux/skbuff.h skb_frag_must_loop() does similar).
>
> But going forward, perhaps CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP is too
> surprising, has outlived its usefulness, and should just be removed?
It has caught real problems and as long as we have highmem support, it
should stay IMO to provide test coverage.
Thanks,
tglx
next prev parent reply other threads:[~2024-10-28 8:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-27 22:23 Hugh Dickins
2024-10-28 8:41 ` Thomas Gleixner [this message]
2024-10-28 18:50 ` Linus Torvalds
2024-10-28 8:55 ` Christoph Hellwig
2024-10-28 12:41 ` Christian Brauner
2024-10-28 14:04 ` Matthew Wilcox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=874j4w4o1f.ffs@tglx \
--to=tglx@linutronix.de \
--cc=akpm@linux-foundation.org \
--cc=brauner@kernel.org \
--cc=djwong@kernel.org \
--cc=hch@lst.de \
--cc=hughd@google.com \
--cc=kent.overstreet@linux.dev \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=peterz@infradead.org \
--cc=torvalds@linuxfoundation.org \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox