There is race condition when call netif_napi_add() after
register_netdevice(), as ->open() can be called without napi initialized
and trigger BUG_ON() on napi_enable(), like on below messages:
[ 9.699863] sky2: driver version 1.30
[ 9.699960] sky2 0000:02:00.0: Yukon-2 EC Ultra chip revision 2
[ 9.700020] sky2 0000:02:00.0: irq 45 for MSI/MSI-X
[ 9.700498] ------------[ cut here ]------------
[ 9.703391] kernel BUG at include/linux/netdevice.h:501!
[ 9.703391] invalid opcode: 0000 [#1] PREEMPT SMP
<snip>
[ 9.830018] Call Trace:
[ 9.830018] [<
fa996169>] sky2_open+0x309/0x360 [sky2]
[ 9.830018] [<
c1007210>] ? via_no_dac+0x40/0x40
[ 9.830018] [<
c1007210>] ? via_no_dac+0x40/0x40
[ 9.830018] [<
c135ed4b>] __dev_open+0x9b/0x120
[ 9.830018] [<
c1431cbe>] ? _raw_spin_unlock_bh+0x1e/0x20
[ 9.830018] [<
c135efd9>] __dev_change_flags+0x89/0x150
[ 9.830018] [<
c135f148>] dev_change_flags+0x18/0x50
[ 9.830018] [<
c13bb8e0>] devinet_ioctl+0x5d0/0x6e0
[ 9.830018] [<
c13bcced>] inet_ioctl+0x6d/0xa0
To fix the problem patch changes the order of initialization.
Bug report:
https://bugzilla.kernel.org/show_bug.cgi?id=67151
Reported-and-tested-by: ebrahim.azarisooreh@gmail.com
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
}
}
+ netif_napi_add(dev, &hw->napi, sky2_poll, NAPI_WEIGHT);
+
err = register_netdev(dev);
if (err) {
dev_err(&pdev->dev, "cannot register net device\n");
netif_carrier_off(dev);
- netif_napi_add(dev, &hw->napi, sky2_poll, NAPI_WEIGHT);
-
sky2_show_addr(dev);
if (hw->ports > 1) {