From: Pavel Machek <pavel@ucw.cz>
To: "Kawai, Hidehiro" <hidehiro.kawai.ez@hitachi.com>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, gregkh@suse.de,
james.bottomley@steeleye.com, Satoshi OSHIMA <soshima@redhat.com>,
"Hideo AOKI@redhat" <haoki@redhat.com>,
sugita <yumiko.sugita.yf@hitachi.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH] binfmt_elf: core dump masking support
Date: Tue, 23 Jan 2007 09:08:39 +0000 [thread overview]
Message-ID: <20070123090838.GD5560@ucw.cz> (raw)
In-Reply-To: <45B59218.4040201@hitachi.com>
On Tue 2007-01-23 13:42:00, Kawai, Hidehiro wrote:
> Hi,
>
> >>>(run echo 1 > coremask, echo 0 > coremask in a loop while dumping
> >>>core. Do you have enough locking to make it work as expected?)
> >>
> >>Currently, any lock isn't acquired. But I think the kernel only
> >>have to preserve the coremask setting in a local variable at the
> >>begining of core dumping. I'm going to do this in the next version.
> >
> > No, I do not think that is enough. At minimum, you'd need atomic_t
> > variable. But I'd recomend against it. Playing with locking is tricky.
>
> Why do you think it is not enough? I think that any locking is not
> needed.
You are wrong.
> unsigned int mask = current->mm->coremask;
Not a valid C; coremask can change from another cpu.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2007-01-23 9:18 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-13 7:14 [PATCH] binfmt_elf: core dump masking support Kawai, Hidehiro
2006-12-13 21:23 ` Andrew Morton
2006-12-18 8:08 ` Kawai, Hidehiro
2006-12-20 15:40 ` Pavel Machek
2007-01-09 1:07 ` Kawai, Hidehiro
2007-01-09 14:39 ` Pavel Machek
2007-01-12 8:49 ` Kawai, Hidehiro
2007-01-14 20:01 ` Pavel Machek
2007-01-19 0:40 ` Kawai, Hidehiro
2007-01-19 0:45 ` Pavel Machek
2007-01-22 2:29 ` Kawai, Hidehiro
2007-01-22 10:06 ` Pavel Machek
2007-01-23 4:42 ` Kawai, Hidehiro
2007-01-23 9:08 ` Pavel Machek [this message]
2007-01-23 12:17 ` Kawai, Hidehiro
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=20070123090838.GD5560@ucw.cz \
--to=pavel@ucw.cz \
--cc=akpm@osdl.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=gregkh@suse.de \
--cc=haoki@redhat.com \
--cc=hidehiro.kawai.ez@hitachi.com \
--cc=james.bottomley@steeleye.com \
--cc=linux-kernel@vger.kernel.org \
--cc=masami.hiramatsu.pt@hitachi.com \
--cc=soshima@redhat.com \
--cc=yumiko.sugita.yf@hitachi.com \
/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