Hello,
In function...
static int __devinit emac_probe(struct of_device *ofdev,
const struct of_device_id *match)
... in
drivers/net/ibm_newemac/core.c
... there is a chunk of code as follows (The // DLW - BUG ... comment is
mine) ...
/* Find PHY if any */
// DLW - BUG - This uses an uninitialized spinlock (potential badness).
err = emac_init_phy(dev);
if (err != 0)
goto err_detach_tah;
/* Fill in the driver function table */
ndev->open = &emac_open;
if (dev->tah_dev)
ndev->features |= NETIF_F_IP_CSUM | NETIF_F_SG;
ndev->tx_timeout = &emac_tx_timeout;
ndev->watchdog_timeo = 5 * HZ;
ndev->stop = &emac_close;
ndev->get_stats = &emac_stats;
ndev->set_multicast_list = &emac_set_multicast_list;
ndev->do_ioctl = &emac_ioctl;
if (emac_phy_supports_gige(dev->phy_mode)) {
ndev->hard_start_xmit = &emac_start_xmit_sg;
ndev->change_mtu = &emac_change_mtu;
dev->commac.ops = &emac_commac_sg_ops;
} else {
ndev->hard_start_xmit = &emac_start_xmit;
}
SET_ETHTOOL_OPS(ndev, &emac_ethtool_ops);
netif_carrier_off(ndev);
netif_stop_queue(ndev);
err = register_netdev(ndev);
if (err) {
printk(KERN_ERR "%s: failed to register net device (%d)!\n",
np->full_name, err);
goto err_detach_tah;
}
init_emac_phy() uses a spinlock that isn't initialized until
register_netdev() is invoked. I tried moving the init_emac_phy() to be
after the register_netdev(). The fix appeared to work on one board
variant (with two Ethernet ports) but kernel panics during boot on
another board variant (with one Etherent port and less memory).
So I have reverted my lame hack attempt and am reporting this so that an
expert can check into it.
The bug normally goes unnoticed until you turn on spinlock and/or
rtmutex debuggging in the kernel config - then the debugging magic
checks will catch it during boot.
This is based on kernel 2.6.25.8-rt7 and then upgraded to be
2.6.25.13-rt7 using incremental patches - running on an AMCC PPC405EP
but I think you could reproduce it using 2.6.25.8-rt7 (or possibly other
kernel versions).
--
Regards,
Darcy
--------------
Darcy L. Watkins - Senior Software Developer
Tranzeo Wireless Technologies, Inc.
19273 Fraser Way, Pitt Meadows, BC, Canada V3Y 2V4
T:604-460-6002 ext:410
http://www.tranzeo.com
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