On Thursday 12/17 at 17:10 -0800, Stephen Hemminger wrote: > On Thu, 17 Dec 2015 15:52:39 -0800 > Calvin Owens <calvinow...@fb.com> wrote: > > > With built-in netconsole and IXGBE, configuring netconsole via the kernel > > cmdline results in the following panic at boot: > > > > netpoll: netconsole: device eth0 not up yet, forcing it > > usb 2-1: new high-speed USB device number 2 using ehci-pci > > ixgbe 0000:03:00.0: registered PHC device on eth0 > > BUG: unable to handle kernel NULL pointer dereference at > > 0000000000000810 > > <snip> > > Call Trace: > > [<ffffffff81578661>] ? vxlan_get_rx_port+0x41/0xa0 > > [<ffffffff81586828>] ixgbe_open+0x4e8/0x540 > > [<ffffffff8168045c>] __dev_open+0xac/0x120 > > [<ffffffff81680506>] dev_open+0x36/0x70 > > [<ffffffff8169abec>] netpoll_setup+0x23c/0x300 > > [<ffffffff8169a66a>] ? netpoll_parse_options+0x19a/0x200 > > [<ffffffff81d797a8>] ? option_setup+0x1f/0x1f > > [<ffffffff81d79882>] init_netconsole+0xda/0x262 > > [<ffffffff81d797a8>] ? option_setup+0x1f/0x1f > > [<ffffffff810003a8>] do_one_initcall+0x88/0x1b0 > > [<ffffffff81d31144>] kernel_init_freeable+0x14a/0x1e3 > > [<ffffffff81d308f1>] ? do_early_param+0x8c/0x8c > > [<ffffffff81778610>] ? rest_init+0x80/0x80 > > [<ffffffff8177861e>] kernel_init+0xe/0xe0 > > [<ffffffff8177dc5f>] ret_from_fork+0x3f/0x70 > > [<ffffffff81778610>] ? rest_init+0x80/0x80 > > > > This happens because IXGBE assumes that vxlan has already been initialized. > > The cleanest way to fix this is to just initialize netconsole after all the > > other core networking stuff has completed. > > > > Signed-off-by: Calvin Owens <calvinow...@fb.com> > > Fixing this by changing Makefile order is too fragile. > You are depending on the fact that Makefile order determines link order > and that determines initialization order. Down that path demons lie.
Hmm, include/linux/init.h explicitly states that "Ordering inside the subsections is determined by link order", and has since before the beginning of the history in Git. I agree it seems magic/scary, but as Eric says I would imagine this behavior is relied upon in other places. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
