Re: [Bugme-new] [Bug 37202] New: Cannot change MTU on bridged interface

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Sat, 11 Jun 2011 10:59:18 GMT
bugzilla-daemon@bugzilla.kernel.org wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=37202

           Summary: Cannot change MTU on bridged interface
           Product: Networking
           Version: 2.5
    Kernel Version: 3.0.0-rc2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: acme@ghostprotocols.net
        ReportedBy: steve-alexander@roadrunner.com
        Regression: No


Without bridge, setting mtu on eth0 works as expected.
When eth0 is added to bridge 'br0' and this command is executed,

ip link set eth0 mtu 4000

results in:

erk.

Is this a new bug in 3.0-rc or have earlier kernels crashed in this manner?

Thanks.

Modules linked in: fuse ip6table_filter ip6_tables ebtable_nat ebtables bridge
stp llc sunrpc ipv6 kvm_intel kvm uinput snd_hda_codec_hdmi
snd_hda_codec_realtek snd_hda_intel snd_hda_codec 
snd_hwdep snd_seq i915 drm_kms_helper snd_seq_device drm iTCO_wdt i2c_algo_bit
i2c_i801 ata_generic pata_acpi usblp i2c_core e1000e xhci_hcd video
iTCO_vendor_support usb_storage snd_pcm se
rio_raw joydev pata_jmicron pcspkr microcode snd_timer snd soundcore
snd_page_alloc [last unloaded: scsi_wait_scan]

Pid: 4247, comm: ip Not tainted 3.0.0-rc2 #4 Gigabyte Technology Co., Ltd.
H57M-USB3/H57M-USB3
RIP: 0010:[<0000000000000000>]  [<          (null)>]           (null)
RSP: 0018:ffff8801e419d680  EFLAGS: 00010202
RAX: 0000000000000640 RBX: 0000000000000640 RCX: ffff880212874788
RDX: ffffffffa0347e00 RSI: ffffffffa0345c21 RDI: ffff880212874fb0
RBP: ffff8801e419d6a8 R08: 0000000000000000 R09: ffffffff81666030
R10: ffffffff81a7a3a0 R11: 0000000000000001 R12: ffff880212874000
R13: ffff880212874780 R14: 00000000ffffffea R15: ffffffffa00e4030
FS:  00007effa3ca6720(0000) GS:ffff88021fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 00000001e401b000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process ip (pid: 4247, threadinfo ffff8801e419c000, task ffff8801f5f14560)
Stack:
 ffffffffa033b1a6 ffff880212874000 00000000ffffffed ffff8801f50af400
 ffff880211dc4000 ffff8801e419d6c8 ffffffff813ba810 0000000000000007
 ffff880212874780 ffff8801e419d6f8 ffffffffa033e2b4 ffff880211dc4000

Call Trace:
 [<ffffffffa033b1a6>] ? br_change_mtu+0x61/0x81 [bridge]
 [<ffffffff813ba810>] dev_set_mtu+0x45/0x75
 [<ffffffffa033e2b4>] br_device_event+0x7c/0x16c [bridge]
 [<ffffffff8146f921>] notifier_call_chain+0x37/0x63
 [<ffffffff8106d934>] raw_notifier_call_chain+0x14/0x16
 [<ffffffff813ba107>] call_netdevice_notifiers+0x4a/0x4f
 [<ffffffff813ba838>] dev_set_mtu+0x6d/0x75
 [<ffffffff813c8da2>] do_setlink+0x1ee/0x739
 [<ffffffff810e8052>] ? set_pte_at+0xe/0x12
 [<ffffffff8122e1de>] ? nla_parse+0x4f/0xc3
 [<ffffffff813c9f45>] rtnl_newlink+0x252/0x48d
 [<ffffffff813c9db7>] ? rtnl_newlink+0xc4/0x48d
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff813af3e3>] ? sock_rmalloc+0x33/0x95
 [<ffffffff813c9afe>] rtnetlink_rcv_msg+0x1eb/0x201
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff813c9913>] ? __rtnl_unlock+0x17/0x17
 [<ffffffff813dd9a8>] netlink_rcv_skb+0x45/0x90
 [<ffffffff813c94c4>] rtnetlink_rcv+0x26/0x2d
 [<ffffffff813dd4b3>] netlink_unicast+0xf1/0x15a
 [<ffffffff813dd7a1>] netlink_sendmsg+0x285/0x2a3
 [<ffffffff8110c558>] ? fatal_signal_pending+0x12/0x29
 [<ffffffff813a9e7d>] __sock_sendmsg+0x6a/0x76
 [<ffffffff813aa764>] sock_sendmsg+0xa8/0xc1
 [<ffffffff810cf7b0>] ? filemap_fault+0x20b/0x36c
 [<ffffffff810cde20>] ? unlock_page+0x2a/0x2f
 [<ffffffff810e8a1a>] ? __do_fault+0x34d/0x384
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff8103d058>] ? should_resched+0xe/0x2e
 [<ffffffff8103d040>] ? need_resched+0x23/0x2d
 [<ffffffff8103d058>] ? should_resched+0xe/0x2e
 [<ffffffff813b406e>] ? copy_from_user+0x2f/0x31
 [<ffffffff813b445e>] ? verify_iovec+0x54/0xa6
 [<ffffffff813aaa1a>] __sys_sendmsg+0x1ee/0x272
 [<ffffffff810eb570>] ? handle_mm_fault+0x149/0x15e
 [<ffffffff8146c5b6>] ? _raw_spin_lock+0xe/0x10
 [<ffffffff8146f8ab>] ? do_page_fault+0x321/0x360
 [<ffffffff810efda4>] ? do_brk+0x242/0x296
 [<ffffffff813ac02f>] sys_sendmsg+0x42/0x60
 [<ffffffff81472d42>] system_call_fastpath+0x16/0x1b
Code:  Bad RIP value.
RIP  [<          (null)>]           (null)
 RSP <ffff8801e419d680>
CR2: 0000000000000000
---[ end trace 29a99239194ab188 ]---


Bridge creation is managed by Fedora14 standard configs.
eth0 is the only interface added to the bridge.

eth0 is 
03:00.0 Ethernet controller [0200]: Intel Corporation 82574L Gigabit Network
Connection [8086:10d3]
    Subsystem: Intel Corporation Gigabit CT Desktop Adapter [8086:a01f]
    Kernel driver in use: e1000e
    Kernel modules: e1000e