Patch "[PATCH 013/135] igb: fix NULL derefs due to skipped SR-IOV enabling" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

[PATCH 013/135] igb: fix NULL derefs due to skipped SR-IOV enabling

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
0013-igb-fix-NULL-derefs-due-to-skipped-SR-IOV-enabling.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jan Beulich <[email protected]>
Date: Mon, 19 Oct 2015 04:23:29 -0600
Subject: [PATCH 013/135] igb: fix NULL derefs due to skipped SR-IOV enabling

[ Upstream commit be06998f96ecb93938ad2cce46c4289bf7cf45bc ]

The combined effect of commits 6423fc3416 ("igb: do not re-init SR-IOV during probe") and ceee3450b3 ("igb: make sure SR-IOV init uses the right number of queues") causes VFs no longer getting set up, leading to NULL pointer dereferences due to the adapter's ->vf_data being NULL while ->vfs_allocated_count is non-zero. The first commit not only neglected the side effect of igb_sriov_reinit() that the second commit tried to account for, but also that of setting IGB_FLAG_HAS_MSIX, without which igb_enable_sriov() is effectively a no-op. Calling igb_{,re}set_interrupt_capability() as done here seems to address this, but I'm not sure whether this is better than sinply reverting the other two commits.

---
 drivers/net/ethernet/intel/igb/igb_main.c |    7 +++++++
 1 file changed, 7 insertions(+)

@@ -2858,6 +2858,13 @@ static void igb_probe_vfs(struct igb_ada
 	if ((hw->mac.type == e1000_i210) || (hw->mac.type == e1000_i211))
 		return;
 
+	/* Of the below we really only want the effect of getting
+	 * IGB_FLAG_HAS_MSIX set (if available), without which
+	 * igb_enable_sriov() has no effect.
+	 */
+	igb_set_interrupt_capability(adapter, true);
+	igb_reset_interrupt_capability(adapter);
+
 	pci_sriov_set_totalvfs(pdev, 7);
 	igb_enable_sriov(pdev, max_vfs);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/0013-igb-fix-NULL-derefs-due-to-skipped-SR-IOV-enabling.patch