From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Assmann Date: Sat, 6 Feb 2016 00:13:00 +0100 Subject: [Intel-wired-lan] [net-next] igb: assume MSI-X interrupts during initialization In-Reply-To: <56B5131D.1070505@redhat.com> References: <1442493970-20073-1-git-send-email-sassmann@kpanic.de> <56B5131D.1070505@redhat.com> Message-ID: <56B52C7C.3000500@kpanic.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On 02/05/2016 10:24 PM, Laine Stump wrote: > 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! Hi Laine, I took a quick look at 4.3 and the patch you mention should be sufficient. For 4.2 I'll have to take a closer look. I'm currently traveling but going to get back to you early next week. I'd like double check things before taking any action. Thanks! Stefan > The full saga of my problem and investigaton is here: > > https://www.mail-archive.com/iommu at 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); >> >