From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laine Stump Subject: Re: [net-next] igb: assume MSI-X interrupts during initialization Date: Fri, 5 Feb 2016 16:24:45 -0500 Message-ID: <56B5131D.1070505@redhat.com> References: <1442493970-20073-1-git-send-email-sassmann@kpanic.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Stefan Assmann , intel-wired-lan@lists.osuosl.org, davem@davemloft.net, jeffrey.t.kirsher@intel.com To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43081 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753837AbcBEVYs (ORCPT ); Fri, 5 Feb 2016 16:24:48 -0500 In-Reply-To: <1442493970-20073-1-git-send-email-sassmann@kpanic.de> Sender: netdev-owner@vger.kernel.org List-ID: Stefan, I have an AMD 990FX system with an Intel 82576 card that could not successfully boot with any kernel starting somewhere prior to 4.2, but does boot properly in 4.4+. After a lot of time bisecting, I found that this patch, when applied to kernel 4.3.0, solves the problem (applying to 4.2.0 has no effect, so there's some other patch/patches in the interim that were also part of the fix). Since I don't know the details of proposing this patch for 4.3 stable, would it be possible for you to do that? Thanks! The full saga of my problem and investigaton is here: https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg10687.html On 09/17/2015 08:46 AM, Stefan Assmann wrote: > In igb_sw_init() the sequence of calls was changed from > igb_init_queue_configuration() > igb_init_interrupt_scheme() > igb_probe_vfs() > to > igb_probe_vfs() > igb_init_queue_configuration() > igb_init_interrupt_scheme() > > This results in adapter->flags not having the IGB_FLAG_HAS_MSIX bit set > during igb_probe_vfs()->igb_enable_sriov(). Therefore SR-IOV does not > get enabled properly and we run into a NULL pointer if the max_vfs > module parameter is specified (adapter->vf_data does not get allocated, > crash on accessing the structure). > > [ 7.419348] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 > [ 7.419367] IP: [] igb_reset+0xe6/0x5d0 [igb] > [ 7.419370] PGD 0 > [ 7.419373] Oops: 0002 [#1] SMP > [ 7.419381] Modules linked in: ahci(+) libahci igb(+) i40e(+) vxlan ip6_udp_tunnel udp_tunnel megaraid_sas(+) ixgbe(+) mdio > [ 7.419385] CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 4.2.0+ #153 > [ 7.419387] Hardware name: Dell Inc. PowerEdge R720/0C4Y3R, BIOS 1.6.0 03/07/2013 > [...] > [ 7.419431] Call Trace: > [ 7.419442] [] igb_probe+0x8b6/0x1340 [igb] > [ 7.419447] [] local_pci_probe+0x45/0xa0 > > Prevent this by setting the IGB_FLAG_HAS_MSIX bit before calling > igb_probe_vfs(). The real interrupt capabilities will be checked during > igb_init_interrupt_scheme() so this is safe to do. > > Signed-off-by: Stefan Assmann > --- > drivers/net/ethernet/intel/igb/igb_main.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c > index e174fbb..ba019fc 100644 > --- a/drivers/net/ethernet/intel/igb/igb_main.c > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > @@ -2986,6 +2986,9 @@ static int igb_sw_init(struct igb_adapter *adapter) > } > #endif /* CONFIG_PCI_IOV */ > > + /* Assume MSI-X interrupts, will be checked during IRQ allocation */ > + adapter->flags |= IGB_FLAG_HAS_MSIX; > + > igb_probe_vfs(adapter); > > igb_init_queue_configuration(adapter); >