Messages in this thread Patch in this message | | | Date | Sun, 15 Jun 2008 21:44:15 +0200 | From | Tobias Diedrich <> | Subject | [PATCH] Re: forcedeth: lockdep warning on ethtool -s |
| |
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。 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |