From: "Alex Bennée" <alex.bennee@linaro.org>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-devel@nongnu.org
Subject: Re: [PATCH for-8.1] accel/tcg: Take mmap_lock in load_atomic16_or_exit
Date: Mon, 17 Jul 2023 19:57:29 +0100 [thread overview]
Message-ID: <875y6iweld.fsf@linaro.org> (raw)
In-Reply-To: <10893737-8628-672d-af7d-7d959d1773f5@linaro.org>
Richard Henderson <richard.henderson@linaro.org> writes:
> On 7/17/23 11:40, Alex Bennée wrote:
>> Richard Henderson <richard.henderson@linaro.org> writes:
>>
>>> For user-only, the probe for page writability may race with another
>>> thread's mprotect. Take the mmap_lock around the operation. This
>>> is still faster than the start/end_exclusive fallback.
>> Did we have a bug report or replication for this?
>
> See the comment:
>
>> + * We must take mmap_lock so that the query remains valid until
>> + * the write is complete -- tests/tcg/multiarch/munmap-pthread.c
>> + * is an example that can race.
doh...
>
>
> r~
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
prev parent reply other threads:[~2023-07-17 18:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-16 17:01 [PATCH for-8.1] accel/tcg: Take mmap_lock in load_atomic16_or_exit Richard Henderson
2023-07-17 10:12 ` Peter Maydell
2023-07-17 15:07 ` Richard Henderson
2023-07-20 12:17 ` Peter Maydell
2023-07-17 10:40 ` Alex Bennée
2023-07-17 15:07 ` Richard Henderson
2023-07-17 18:57 ` Alex Bennée [this message]
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=875y6iweld.fsf@linaro.org \
--to=alex.bennee@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=richard.henderson@linaro.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;
as well as URLs for NNTP newsgroup(s).