From: Patrick McHardy <kaber@trash.net>
To: ranko@spidernet.net
Cc: Andrew Morton <akpm@linux-foundation.org>,
netdev@vger.kernel.org,
"bugme-daemon@kernel-bugs.osdl.org"
<bugme-daemon@kernel-bugs.osdl.org>
Subject: Re: [Bugme-new] [Bug 8736] New: New TC deadlock scenario
Date: Wed, 11 Jul 2007 20:31:12 +0200 [thread overview]
Message-ID: <469521F0.1010803@trash.net> (raw)
In-Reply-To: <20070711111803.f8f97d98.akpm@linux-foundation.org>
Andrew Morton wrote:
>>http://bugzilla.kernel.org/show_bug.cgi?id=8736
>>
>>Here is another scenario I bumped onto - qdisc_watchdog_cancel() and
>>qdisc_restart() deadlock.
>>
>>CPU#0
>>qdisc_watchdog() fires and gets dev->queue_lock
>>qdisc_run()...qdisc_restart()...
>>-> releases dev->queue_lock and enters dev_hard_start_xmit()
>>
>>CPU#1
>>tc del qdisc dev ...
>>qdisc_graft()...dev_graft_qdisc()...dev_deactivate()...
>>-> grabs dev->queue_lock ...
>>qdisc_reset()...{cbq,hfsc,htb,netem,tbf}_reset()...qdisc_watchdog_cancel()...
>>-> hrtimer_cancel() - waiting for the qdisc_watchdog() to exit, while still
>>holding dev->queue_lock
>>
>>CPU#0
>>dev_hard_start_xmit() returns ...
>>-> wants to get dev->queue_lock(!)
>>
>>DEADLOCK!
Good catch.
Please try reverting commit 1936502d00ae6c2aa3931c42f6cf54afaba094f2,
that should fix it.
next prev parent reply other threads:[~2007-07-11 18:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-8736-10286@http.bugzilla.kernel.org/>
2007-07-11 18:18 ` [Bugme-new] [Bug 8736] New: New TC deadlock scenario Andrew Morton
2007-07-11 18:31 ` Patrick McHardy [this message]
2007-07-14 15:43 ` Patrick McHardy
2007-07-14 16:45 ` Ranko Zivojnovic
2007-07-15 3:49 ` David Miller
2007-07-15 14:21 ` Patrick McHardy
2007-07-16 0:36 ` David Miller
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