* forcedeth: lockdep warning on ethtool -s
@ 2008-06-01 8:37 Tobias Diedrich
2008-06-06 5:18 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Tobias Diedrich @ 2008-06-01 8:37 UTC (permalink / raw)
To: netdev, linux-kernel, Ayaz Abdulla
Hi,
After enabling CONFIG_LOCKDEP and CONFIG_PROVE_LOCKING I get the
following warning when ethtool -s is first called on one of the
forcedeth ports:
=================================
[ INFO: inconsistent lock state ]
2.6.26-rc4 #28
---------------------------------
inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
ethtool/1985 [HC0[0]:SC0[1]:HE1:SE0] takes:
(&np->lock){++..}, at: [<ffffffffa000c5fd>] nv_set_settings+0xc8/0x3de [forcedeth]
{in-hardirq-W} state was registered at:
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 3606
hardirqs last enabled at (3605): [<ffffffff8068106f>] _spin_unlock_irqrestore+0x3f/0x68
hardirqs last disabled at (3604): [<ffffffff80680d38>] _spin_lock_irqsave+0x13/0x46
softirqs last enabled at (3534): [<ffffffff80246ba5>] __do_softirq+0xbc/0xc5
softirqs last disabled at (3606): [<ffffffff80680b33>] _spin_lock_bh+0x11/0x41
other info that might help us debug this:
2 locks held by ethtool/1985:
#0: (rtnl_mutex){--..}, at: [<ffffffff80596072>] rtnl_lock+0x12/0x14
#1: (_xmit_ETHER){-+..}, at: [<ffffffffa000c5e8>] nv_set_settings+0xb3/0x3de [forcedeth]
stack backtrace:
Pid: 1985, comm: ethtool Not tainted 2.6.26-rc4 #28
Call Trace:
[<ffffffff8025f190>] print_usage_bug+0x162/0x173
[<ffffffff8025fa8b>] mark_lock+0x231/0x41f
[<ffffffff802607cf>] __lock_acquire+0x4e7/0xcac
[<ffffffff8025fe64>] ? trace_hardirqs_on+0xf1/0x115
[<ffffffff80272c3a>] ? disable_irq_nosync+0x6f/0x7b
[<ffffffff80261375>] lock_acquire+0x55/0x6e
[<ffffffffa000c5fd>] ? :forcedeth:nv_set_settings+0xc8/0x3de
[<ffffffff80680b15>] _spin_lock+0x2f/0x3c
[<ffffffffa000c5fd>] :forcedeth:nv_set_settings+0xc8/0x3de
[<ffffffff8058f8bb>] dev_ethtool+0x186/0xea3
[<ffffffff8067f446>] ? mutex_lock_nested+0x243/0x275
[<ffffffff8025df2b>] ? debug_mutex_free_waiter+0x46/0x4a
[<ffffffff8067f469>] ? mutex_lock_nested+0x266/0x275
[<ffffffff8058e1ce>] dev_ioctl+0x4eb/0x600
[<ffffffff8068106f>] ? _spin_unlock_irqrestore+0x3f/0x68
[<ffffffff80580f91>] sock_ioctl+0x1f5/0x202
[<ffffffff802a322e>] vfs_ioctl+0x2a/0x77
[<ffffffff802a34d6>] do_vfs_ioctl+0x25b/0x270
[<ffffffff806807b6>] ? trace_hardirqs_on_thunk+0x35/0x3a
[<ffffffff802a352d>] sys_ioctl+0x42/0x65
[<ffffffff8021fffb>] system_call_after_swapgs+0x7b/0x80
I think this is caused by the following snippet in nv_set_settings:
netif_carrier_off(dev);
if (netif_running(dev)) {
nv_disable_irq(dev);
netif_tx_lock_bh(dev);
spin_lock(&np->lock);
/* stop engines */
nv_stop_rxtx(dev);
spin_unlock(&np->lock);
netif_tx_unlock_bh(dev);
}
Because of nv_disable_irq this is probably not really a problem
though (I guess) and replacing the spin_lock with spin_lock_irqsave
could keep interrupts disabled for a longer period of time because
of delays in nv_stop_rx and nv_stop_tx.
--
Tobias PGP: http://9ac7e0bc.uguu.de
このメールは十割再利用されたビットで作られています。
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: forcedeth: lockdep warning on ethtool -s
2008-06-01 8:37 forcedeth: lockdep warning on ethtool -s Tobias Diedrich
@ 2008-06-06 5:18 ` Andrew Morton
2008-06-15 19:44 ` [PATCH] " Tobias Diedrich
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2008-06-06 5:18 UTC (permalink / raw)
To: Tobias Diedrich; +Cc: netdev, linux-kernel, Ayaz Abdulla
On Sun, 1 Jun 2008 10:37:01 +0200 Tobias Diedrich <ranma+kernel@tdiedrich.de> wrote:
> Hi,
>
> After enabling CONFIG_LOCKDEP and CONFIG_PROVE_LOCKING I get the
> following warning when ethtool -s is first called on one of the
> forcedeth ports:
>
> =================================
> [ INFO: inconsistent lock state ]
> 2.6.26-rc4 #28
> ---------------------------------
> inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
> ethtool/1985 [HC0[0]:SC0[1]:HE1:SE0] takes:
> (&np->lock){++..}, at: [<ffffffffa000c5fd>] nv_set_settings+0xc8/0x3de [forcedeth]
> {in-hardirq-W} state was registered at:
> [<ffffffffffffffff>] 0xffffffffffffffff
> irq event stamp: 3606
> hardirqs last enabled at (3605): [<ffffffff8068106f>] _spin_unlock_irqrestore+0x3f/0x68
> hardirqs last disabled at (3604): [<ffffffff80680d38>] _spin_lock_irqsave+0x13/0x46
> softirqs last enabled at (3534): [<ffffffff80246ba5>] __do_softirq+0xbc/0xc5
> softirqs last disabled at (3606): [<ffffffff80680b33>] _spin_lock_bh+0x11/0x41
>
> other info that might help us debug this:
> 2 locks held by ethtool/1985:
> #0: (rtnl_mutex){--..}, at: [<ffffffff80596072>] rtnl_lock+0x12/0x14
> #1: (_xmit_ETHER){-+..}, at: [<ffffffffa000c5e8>] nv_set_settings+0xb3/0x3de [forcedeth]
>
> stack backtrace:
> Pid: 1985, comm: ethtool Not tainted 2.6.26-rc4 #28
>
> Call Trace:
> [<ffffffff8025f190>] print_usage_bug+0x162/0x173
> [<ffffffff8025fa8b>] mark_lock+0x231/0x41f
> [<ffffffff802607cf>] __lock_acquire+0x4e7/0xcac
> [<ffffffff8025fe64>] ? trace_hardirqs_on+0xf1/0x115
> [<ffffffff80272c3a>] ? disable_irq_nosync+0x6f/0x7b
> [<ffffffff80261375>] lock_acquire+0x55/0x6e
> [<ffffffffa000c5fd>] ? :forcedeth:nv_set_settings+0xc8/0x3de
> [<ffffffff80680b15>] _spin_lock+0x2f/0x3c
> [<ffffffffa000c5fd>] :forcedeth:nv_set_settings+0xc8/0x3de
> [<ffffffff8058f8bb>] dev_ethtool+0x186/0xea3
> [<ffffffff8067f446>] ? mutex_lock_nested+0x243/0x275
> [<ffffffff8025df2b>] ? debug_mutex_free_waiter+0x46/0x4a
> [<ffffffff8067f469>] ? mutex_lock_nested+0x266/0x275
> [<ffffffff8058e1ce>] dev_ioctl+0x4eb/0x600
> [<ffffffff8068106f>] ? _spin_unlock_irqrestore+0x3f/0x68
> [<ffffffff80580f91>] sock_ioctl+0x1f5/0x202
> [<ffffffff802a322e>] vfs_ioctl+0x2a/0x77
> [<ffffffff802a34d6>] do_vfs_ioctl+0x25b/0x270
> [<ffffffff806807b6>] ? trace_hardirqs_on_thunk+0x35/0x3a
> [<ffffffff802a352d>] sys_ioctl+0x42/0x65
> [<ffffffff8021fffb>] system_call_after_swapgs+0x7b/0x80
>
>
> I think this is caused by the following snippet in nv_set_settings:
>
> netif_carrier_off(dev);
> if (netif_running(dev)) {
> nv_disable_irq(dev);
> netif_tx_lock_bh(dev);
> spin_lock(&np->lock);
> /* stop engines */
> nv_stop_rxtx(dev);
> spin_unlock(&np->lock);
> netif_tx_unlock_bh(dev);
> }
>
>
> Because of nv_disable_irq this is probably not really a problem
> though (I guess) and replacing the spin_lock with spin_lock_irqsave
> could keep interrupts disabled for a longer period of time because
> of delays in nv_stop_rx and nv_stop_tx.
Could you please try that and if it works, send the patch?
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] Re: forcedeth: lockdep warning on ethtool -s
2008-06-06 5:18 ` Andrew Morton
@ 2008-06-15 19:44 ` Tobias Diedrich
0 siblings, 0 replies; 3+ messages in thread
From: Tobias Diedrich @ 2008-06-15 19:44 UTC (permalink / raw)
To: Andrew Morton; +Cc: netdev, linux-kernel, Ayaz Abdulla
Andrew Morton wrote:
> On Sun, 1 Jun 2008 10:37:01 +0200 Tobias Diedrich <ranma+kernel@tdiedrich.de> wrote:
>
> > Hi,
> >
> > After enabling CONFIG_LOCKDEP and CONFIG_PROVE_LOCKING I get the
> > following warning when ethtool -s is first called on one of the
> > forcedeth ports:
> >
> > =================================
> > [ INFO: inconsistent lock state ]
> > 2.6.26-rc4 #28
> > ---------------------------------
> > inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
> > ethtool/1985 [HC0[0]:SC0[1]:HE1:SE0] takes:
> > (&np->lock){++..}, at: [<ffffffffa000c5fd>] nv_set_settings+0xc8/0x3de [forcedeth]
> > {in-hardirq-W} state was registered at:
> > [<ffffffffffffffff>] 0xffffffffffffffff
> > irq event stamp: 3606
> > hardirqs last enabled at (3605): [<ffffffff8068106f>] _spin_unlock_irqrestore+0x3f/0x68
> > hardirqs last disabled at (3604): [<ffffffff80680d38>] _spin_lock_irqsave+0x13/0x46
> > softirqs last enabled at (3534): [<ffffffff80246ba5>] __do_softirq+0xbc/0xc5
> > softirqs last disabled at (3606): [<ffffffff80680b33>] _spin_lock_bh+0x11/0x41
> >
> > other info that might help us debug this:
> > 2 locks held by ethtool/1985:
> > #0: (rtnl_mutex){--..}, at: [<ffffffff80596072>] rtnl_lock+0x12/0x14
> > #1: (_xmit_ETHER){-+..}, at: [<ffffffffa000c5e8>] nv_set_settings+0xb3/0x3de [forcedeth]
> >
> > stack backtrace:
> > Pid: 1985, comm: ethtool Not tainted 2.6.26-rc4 #28
> >
> > Call Trace:
> > [<ffffffff8025f190>] print_usage_bug+0x162/0x173
> > [<ffffffff8025fa8b>] mark_lock+0x231/0x41f
> > [<ffffffff802607cf>] __lock_acquire+0x4e7/0xcac
> > [<ffffffff8025fe64>] ? trace_hardirqs_on+0xf1/0x115
> > [<ffffffff80272c3a>] ? disable_irq_nosync+0x6f/0x7b
> > [<ffffffff80261375>] lock_acquire+0x55/0x6e
> > [<ffffffffa000c5fd>] ? :forcedeth:nv_set_settings+0xc8/0x3de
> > [<ffffffff80680b15>] _spin_lock+0x2f/0x3c
> > [<ffffffffa000c5fd>] :forcedeth:nv_set_settings+0xc8/0x3de
> > [<ffffffff8058f8bb>] dev_ethtool+0x186/0xea3
> > [<ffffffff8067f446>] ? mutex_lock_nested+0x243/0x275
> > [<ffffffff8025df2b>] ? debug_mutex_free_waiter+0x46/0x4a
> > [<ffffffff8067f469>] ? mutex_lock_nested+0x266/0x275
> > [<ffffffff8058e1ce>] dev_ioctl+0x4eb/0x600
> > [<ffffffff8068106f>] ? _spin_unlock_irqrestore+0x3f/0x68
> > [<ffffffff80580f91>] sock_ioctl+0x1f5/0x202
> > [<ffffffff802a322e>] vfs_ioctl+0x2a/0x77
> > [<ffffffff802a34d6>] do_vfs_ioctl+0x25b/0x270
> > [<ffffffff806807b6>] ? trace_hardirqs_on_thunk+0x35/0x3a
> > [<ffffffff802a352d>] sys_ioctl+0x42/0x65
> > [<ffffffff8021fffb>] system_call_after_swapgs+0x7b/0x80
> >
> >
> > I think this is caused by the following snippet in nv_set_settings:
> >
> > netif_carrier_off(dev);
> > if (netif_running(dev)) {
> > nv_disable_irq(dev);
> > netif_tx_lock_bh(dev);
> > spin_lock(&np->lock);
> > /* stop engines */
> > nv_stop_rxtx(dev);
> > spin_unlock(&np->lock);
> > netif_tx_unlock_bh(dev);
> > }
> >
> >
> > Because of nv_disable_irq this is probably not really a problem
> > though (I guess) and replacing the spin_lock with spin_lock_irqsave
> > could keep interrupts disabled for a longer period of time because
> > of delays in nv_stop_rx and nv_stop_tx.
>
> Could you please try that and if it works, send the patch?
Here you go, with this patch applied I get no warning:
Signed-Off-By: Tobias Diedrich <ranma+kernel@tdiedrich.de>
Index: linux-2.6.26-rc4.forcedwol/drivers/net/forcedeth.c
===================================================================
--- linux-2.6.26-rc4.forcedwol.orig/drivers/net/forcedeth.c 2008-06-15 20:45:32.000000000 +0200
+++ linux-2.6.26-rc4.forcedwol/drivers/net/forcedeth.c 2008-06-15 20:55:27.000000000 +0200
@@ -4198,12 +4198,23 @@
netif_carrier_off(dev);
if (netif_running(dev)) {
+ unsigned long flags;
+
nv_disable_irq(dev);
netif_tx_lock_bh(dev);
- spin_lock(&np->lock);
+ /* with plain spinlock lockdep complains */
+ spin_lock_irqsave(&np->lock, flags);
/* stop engines */
+ /* FIXME:
+ * this can take some time, and interrupts are disabled
+ * due to spin_lock_irqsave, but let's hope no daemon
+ * is going to change the settings very often...
+ * Worst case:
+ * NV_RXSTOP_DELAY1MAX + NV_TXSTOP_DELAY1MAX
+ * + some minor delays, which is up to a second approximately
+ */
nv_stop_rxtx(dev);
- spin_unlock(&np->lock);
+ spin_unlock_irqrestore(&np->lock, flags);
netif_tx_unlock_bh(dev);
}
--
Tobias PGP: http://9ac7e0bc.uguu.de
このメールは十割再利用されたビットで作られています。
^ permalink raw reply [flat|nested] 3+ messages in thread
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2008-06-06 5:18 ` Andrew Morton
2008-06-15 19:44 ` [PATCH] " Tobias Diedrich
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