This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed- cosmic' to 'verification-done-cosmic'. If the problem still exists, change the tag 'verification-needed-cosmic' to 'verification-failed- cosmic'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: verification-needed-cosmic -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1796748 Title: regression in 'ip --family bridge neigh' since linux v4.12 Status in linux package in Ubuntu: Triaged Status in linux source package in Bionic: Fix Committed Bug description: [Impact] * Netlink RTM_GETNEIGH requests for PF_BRIDGE are broken since linux v4.12. * Users, tools (e.g., iproute2), and libraries (e.g., go netlink) that use such request/family currently receive nothing back in the kernel response. * The upstream fix resolves the breakage in the userspace-kernel interface by explicitly checking for the old/broken request to ensure it's replied. [Test Case] * The command 'ip --family bridge neigh' returns nothing on broken kernels, and matches 'bridge fdb show' on fixed kernels. * Before: $ ip --family bridge neigh $ * After: $ ip --family bridge neigh dev ens3 lladdr 33:33:00:00:00:01 PERMANENT dev ens3 lladdr 01:00:5e:00:00:01 PERMANENT dev ens3 lladdr 33:33:ff:e9:9d:60 PERMANENT * Reference: $ bridge fdb show 33:33:00:00:00:01 dev ens3 self permanent 01:00:5e:00:00:01 dev ens3 self permanent 33:33:ff:e9:9d:60 dev ens3 self permanent [Regression Potential] * Low, for three reasons: * The fix is fairly contained (RTM_GETNEIGH request for PF_BRIDGE family). * The checks introduced by the fix are conservative, based on the size of the old request (the size of the old/new requests are different), and it does nothing different in case the (old) size doesn't match. * Given the above, only applications with message length and contents specially hand-crafted (and likely not valid nor useful) might fail. To the best of my knowledge, this is not the common case out there. [Other Info] * The patch is only applicable to v4.12+ (so not Trusty nor Xenial). * The patch is the same for Bionic, Cosmic, and unstable. * Upstream commit: bd961c9bc664 ("rtnetlink: fix rtnl_fdb_dump() for ndmsg header") https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bd961c9bc66497f0c63f4ba1d02900bb85078366 * I'll submit the patch shortly to the kernel-team mailing list. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1796748/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
