[PATCH] hrtimer: fix hrtimer_init_sleeper() users
From: Peter Zijlstra
Date: Thu Jan 31 2008 - 09:28:12 EST
On Thu, 2008-01-31 at 00:42 +0100, Rafael J. Wysocki wrote:
> Update.
>
> On Wednesday, 30 of January 2008, Rafael J. Wysocki wrote:
> > Hi,
> >
> > Recently I've been observing problems with unmounting the /home fs on reboot
> > and/or shutdown on two test boxes.
> >
> > After some more investigation I've found that this is due to some KDE processes
> > stuck in D states after their owner has logged out.
> >
> > This happens 100% of the time if there's a suspend/resume cycle before the user
> > logs out (ie. the user logs into KDE, works for some time, suspends the box to
> > RAM and resmes one or more times and then logs out). Still, I also observe the
> > symptoms on a box that's never suspended.
> >
> > I'm not sure how to debug this, so please advise.
>
> After reverting:
>
> commit 37bb6cb4097e29ffee970065b74499cbf10603a3
> Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Date: Fri Jan 25 21:08:32 2008 +0100
>
> hrtimer: unlock hrtimer_wakeup
>
> I no longer get processes in the D state, but there still is a problem with
> artswrapper (this is an openSUSE 10.3 system, x86-64). Namely,
> after a suspend/resume cycle and logging out/logging in the user,
> artswrapper gets stuck somewhere, apparently in the running (R) state.
> For this reason it blocks any subsequent attempts to suspend.
>
> Here's the relevant trace (from show_state()):
>
> [ 522.474919] artswrapper R running task 0 4805 1
> [ 522.474922] ffff810074cd1f70 0000000000000082 0000000000000296 ffff810074cd1ed8
> [ 522.474926] ffffffff80311769 ffff810074cd1f20 ffffffff80701240 ffffffff80701240
> [ 522.474930] ffffffff80701240 ffffffff80701240 ffffffff80701240 ffffffff80701240
> [ 522.474933] Call Trace:
> [ 522.474940] [<ffffffff80311769>] ? __up_read+0x8f/0x97
> [ 522.474963] [<ffffffff8020c5cf>] retint_careful+0xd/0x21
>
> where, according to gdb,
>
> (gdb) l *__up_read+0x8f
> 0xffffffff80311769 is in __up_read (/home/rafael/src/linux-2.6/lib/rwsem-spinlock.c:273).
> 268
> 269 if (--sem->activity == 0 && !list_empty(&sem->wait_list))
> 270 sem = __rwsem_wake_one_writer(sem);
> 271
> 272 spin_unlock_irqrestore(&sem->wait_lock, flags);
> 273 }
> 274
> 275 /*
> 276 * release a write lock on the semaphore
> 277 */
>
> What gives?
Well, let me give you something that worked for Guillaume :-)
---
Subject: hrtimer: fix hrtimer_init_sleeper() users
commit 37bb6cb4097e29ffee970065b74499cbf10603a3
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Date: Fri Jan 25 21:08:32 2008 +0100
hrtimer: unlock hrtimer_wakeup
Broke hrtimer_init_sleeper() users. It forgot to fix up the futex
caller of this function to detect the failed queueing and messed up
the do_nanosleep() caller in that it could leak a TASK_INTERRUPTIBLE
state.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
kernel/futex.c | 2 ++
kernel/hrtimer.c | 2 ++
2 files changed, 4 insertions(+)
Index: linux-2.6/kernel/hrtimer.c
===================================================================
--- linux-2.6.orig/kernel/hrtimer.c
+++ linux-2.6/kernel/hrtimer.c
@@ -1312,6 +1312,8 @@ static int __sched do_nanosleep(struct h
} while (t->task && !signal_pending(current));
+ __set_current_state(TASK_RUNNING);
+
return t->task == NULL;
}
Index: linux-2.6/kernel/futex.c
===================================================================
--- linux-2.6.orig/kernel/futex.c
+++ linux-2.6/kernel/futex.c
@@ -1252,6 +1252,8 @@ static int futex_wait(u32 __user *uaddr,
t.timer.expires = *abs_time;
hrtimer_start(&t.timer, t.timer.expires, HRTIMER_MODE_ABS);
+ if (!hrtimer_active(&t->timer))
+ t->task = NULL;
/*
* the timer could have already expired, in which
--
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