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: [<ffffffffa02161c6>] 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] [<ffffffffa0217236>] igb_probe+0x8b6/0x1340 [igb]
[ 7.419447] [<ffffffff814c7f15>] 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 <sassm...@kpanic.de>
---
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);
