On Mon, 12 Feb 2007 09:36:09 +0100 Jarek Poplawski <[EMAIL PROTECTED]> wrote:
> On 06-02-2007 22:57, Andrew Morton wrote: > ... > > First time slattach is run to set up a SLIP line all is ok. > > If slattach process is then killed and restarted it fails with message: > > SLIP_set_disc(1): File exists > > Problem still occurs in 2.6.20rc6 kernel > > > > dmesg shows: > > object_add failed for sl0 with -EEXIST, don't try to register things > > with the same name in the same directory. > > [<c01b7b54>] kobject_add+0x147/0x16d > > [<c0211209>] class_device_add+0x9d/0x3b3 > > [<c022829d>] register_netdevice+0x21a/0x2d0 > > [<c8903213>] slip_open+0x3a1/0x4e2 [slip] > > [<c01fc709>] tty_ioctl+0x922/0xbac > ... > > Steps to reproduce: > > (requires a serial port but nothing needs to be attached to it): > > # slattach -L -vd -p slip -s 115200 /dev/ttyS0 > ... > > slip started on /dev/ttyS0 interface sl0 > > > > Above is OK, now kill process with CTRL-C > > > > slattach: tty_set_speed: 0 > > # slattach -L -vd -p slip -s 115200 /dev/ttyS0 > ... > > SLIP_set_disc(1): File exists > ... > > I believe this is called by this changeset : > > http://www2.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.17.y.git;a=commit;h=b17a7c179dd3ce7d04373fddf660eda21efc9db9 > > I think Martin is probably right here. > > It would be useful to check if time has anything to do > with this and wait longer (e.g. >= 1 min.) before the > second slattach. > > Anyway, even if there is some other reason, the above > trace shows (IMHO) some inconsistency in register/ > unregister_netdevice: if class_device_add is reached > it means the name is valid (so was unregistered) and > EEXIST from netdev_register_sysfs is wrong about the > state of this device. So maybe there should be some > warning plus some delayed action instead of register > cancelled? > > Regards, > Jarek P. The problem is that the code in sl_alloc() tries to clear out an net device by calling unregister_netdevice(), the device won't actually disappear until after rtnl_unlock. This whole idea of searching for unused devices is racy crap and needs to go. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
