From: TeJun Huh <tejun@aratech.co.kr>
To: linux-kernel@vger.kernel.org
Subject: Re: Race condition in 2.4 tasklet handling (cli() broken?)
Date: Sat, 23 Aug 2003 13:09:31 +0900 [thread overview]
Message-ID: <20030823040931.GA3872@atj.dyndns.org> (raw)
In-Reply-To: <20030823025448.GA32547@atj.dyndns.org>
Additional suspicious things.
1. tasklet_kill() has similar race condition. mb() required before
tasklet_unlock_wait().
2. local_bh_count() and global_bh_lock tests inside wait_on_irq()
suggests that cli() tries to block not only interrupt handling but all
softirq handlings of all cpus; however, current implementation does
not guarantee that.
Because local_bh_count is adjusted in do_softirq() _after_
decrementing local_irq_count(), other cpus may happily begin
softirq/tasklet/bh handling while a cpu is inside cli() - sti()
critical section.
If softirq handling is not guaranteed to be blocked during cli() -
sti() critical section, local_bh_count() and global_bh_lock tests
inside wait_on_irq() are redundant, and if it should be guranteed,
current implementation seems broken.
--
tejun
next prev parent reply other threads:[~2003-08-23 4:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-23 2:54 Race condition in 2.4 tasklet handling TeJun Huh
2003-08-23 4:09 ` TeJun Huh [this message]
2003-08-23 5:26 ` Race condition in 2.4 tasklet handling (cli() broken?) TeJun Huh
2003-08-23 10:28 ` Stephan von Krawczynski
2003-08-23 15:13 ` TeJun Huh
2003-08-23 15:37 ` Stephan von Krawczynski
2003-08-25 6:31 ` TeJun Huh
2003-08-25 7:23 ` Stephan von Krawczynski
2003-08-26 0:27 ` TeJun Huh
2003-08-23 15:56 ` Stephan von Krawczynski
2003-08-23 16:36 ` TeJun Huh
2003-08-24 3:27 ` TeJun Huh
2003-08-23 15:04 ` Race condition in 2.4 tasklet handling Anton Blanchard
[not found] <nKwX.1yy.17@gated-at.bofh.it>
2003-08-25 8:06 ` Race condition in 2.4 tasklet handling (cli() broken?) Peter T. Breuer
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=20030823040931.GA3872@atj.dyndns.org \
--to=tejun@aratech.co.kr \
--cc=linux-kernel@vger.kernel.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
all inboxes | Powered by JetHome®