From: Ingo Molnar <mingo@elte.hu>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Ulrich Drepper <drepper@redhat.com>
Subject: Re: [patch 2/4] rt-mutex: Fix chain walk early wakeup bug
Date: Fri, 8 Jun 2007 09:18:41 +0200 [thread overview]
Message-ID: <20070608071841.GC30226@elte.hu> (raw)
In-Reply-To: <20070607235801.494414000@linutronix.de>
* Thomas Gleixner <tglx@linutronix.de> wrote:
> +++ linux-2.6.22-rc4/kernel/rtmutex.c 2007-06-08 01:39:38.000000000 +0200
> @@ -189,6 +189,19 @@ int rt_mutex_adjust_prio_chain(struct ta
> if (!waiter || !waiter->task)
> goto out_unlock_pi;
>
> + /*
> + * Check the orig_waiter state. After we dropped the locks,
> + * the previous owner of the lock might have released the lock
> + * and made us the pending owner:
> + */
> + if (orig_waiter && !orig_waiter->task)
> + goto out_unlock_pi;
> +
> + /*
> + * Drop out, when the task has no waiters. Note,
> + * top_waiter can be NULL, when we are in the deboosting
> + * mode!
> + */
> if (top_waiter && (!task_has_pi_waiters(task) ||
> top_waiter != task_top_pi_waiter(task)))
> goto out_unlock_pi;
nice fix! I'm wondering why we never triggered this case with in-kernel
locks in -rt?
Acked-by: Ingo Molnar <mingo@elte.hu>
Ingo
next prev parent reply other threads:[~2007-06-08 7:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-08 0:29 [patch 0/4] PI-Futex bugfixes and cleanups Thomas Gleixner
2007-06-08 0:29 ` [patch 1/4] rt-mutex: Fix stale return value Thomas Gleixner
2007-06-08 7:20 ` Ingo Molnar
2007-06-08 0:29 ` [patch 2/4] rt-mutex: Fix chain walk early wakeup bug Thomas Gleixner
2007-06-08 7:18 ` Ingo Molnar [this message]
2007-06-08 0:29 ` [patch 3/4] pi-futex: Fix exit races and locking problems Thomas Gleixner
2007-06-08 7:16 ` Ingo Molnar
2007-06-08 0:29 ` [patch 4/4] FUTEX: Tidy up the code Thomas Gleixner
2007-06-08 7:10 ` Ingo Molnar
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=20070608071841.GC30226@elte.hu \
--to=mingo@elte.hu \
--cc=akpm@linux-foundation.org \
--cc=drepper@redhat.com \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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